[Building Buildings]

19 hours ago, IvyTechEngineer said:

I am working on my dog house design now. Not sure the best way to do that. Also, maybe I could add some loop cuts around the edges and paint them black to make the outline look better?

 

If Chic's mantra is "testing, testing, testing," mine would be "reference images,  ref. images,  ref. images".

Check out some dog house images with google.

For example simply adding some trim will better define the edges :

 

 

[Building Buildings]

 

On 10/23/2023 at 8:42 PM, IvyTechEngineer said:

In the past I have never had any luck with applying multiple textures to an object I have built and uploaded.

 

On 10/22/2023 at 7:28 PM, IvyTechEngineer said:

 

From your Blender screenshot you appear to have successfully  added 5 material slots and applied them to relevant faces of your model so it is not clear to me what part of this process you are having problems with ?

 

On 10/23/2023 at 8:42 PM, IvyTechEngineer said:

Also, when the object is downloaded the textures are not downloaded as well, I think. 

Don't worry about this. Very very few people upload there image textures along with the model. There is almost no advantage in trying to do this. Just do like every body else and upload your textures as  separate uploads and then apply them to your model inworld using the SL edit floater. 

[Building Buildings]

I'm not happy with my previous post,  it makes it appear as if there is only one way to unwrap and edit the UVs etc of your model  when really there are others that are perhaps less complicated like for example in orthographic view, selecting individual walls and UV unwrapping using the Project from View ( Bounds) method ............

Since you're already familiar with UV unwrapping, you just need to keep in mind that you'll be applying a seamless tileable texture to each material surface and edit the UVs accordingly.

If necessary, additional texture re-scaling and offsetting can be performed in SL using the edit build floater.

 Put on your engineers white (or is it red for engineers?) safety helmet and do what engineers do best, solving problems

 

 

[Building Buildings]

16 hours ago, IvyTechEngineer said:

I attempted to create 5 materials for the building floor. Most of the videos I watch don't show you how to merge all the images into a single image for upload for a single mesh model to Second Life.

You don't merge all the images into a single image !

1 Seamless tilable image texture for each material.

In Blender you unwrap all 5 materials to a single UV map. Think of each material UV's as  a layer in the UV space. So each material will be unwrapped to its own "layer" . If, in Edit mode you now select all of the model, the UV's will look a mess because all the material UV's will be stacked on top of each other. This is not a problem because whether in Blender or in SL, when you select by material to assign an image texture to the  faces only the UV's of this material will be selected.

 

16 hours ago, IvyTechEngineer said:

Maybe I need to create a new image that has all the textures I want and adjust the uv map (this is what I did using Paint).

No. A model this size will be using seamless tileable image textures on its surfaces. These Image textures do not need to be applied in Blender. In Blender all you need to do is assign a test grid to each material so that you can check the orientation of the Uv's in the UV space. At the same time we are checking that the scaling of the Uv islands of a single material are all approximately at the same scale, And checking that the scale the UV's of all the materials are also at a similar scale to one another, though this is less important because the individual image texture can be rescaled when applied in SL.

In Blender we test with a UV grid then in SL we apply a seamless tileable texture to each set of material faces. If you have these image textures on your hard-rive (downloaded from the internet or created yourself in Paint) then of course you can test them out in Blender as well. Any seamless textures you have will be uploaded separately from the mesh. Or you buy some seamless tileable textures from the many  texture suppliers stores inworld or from the SL MP.

So all you need to do in Blender is mark seams, UV unwrap and edit the UV's so they are orientated correctly.

Best is, after marking seams and assigning the 5 materials , in edit mode select all of the model and UV unwrap everything in one go. This will result in all the UV islands having approx. the same scale. Then edit these islands to suit. If some of the UV's are a little deformed (edges that should be aligned to X or Y are off) then try unwrapping again either using the Conformal or Angle Base method :

There are different ways you could unwrap this particular model, below is an example of unwrapping using UV seams and aiming to have, where possible, a single UV island for each material.

 For example the exterior walls:

If we mark a single vertical UV seam somewhere on the exterior walls this should unwrap nicely as a single continuos UV island,  The seamless texture will wrap around the exterior walls with only a single join where the UV seam was placed.

The same for all the other walls and floors. If UV seams are placed correctly each material UV will be a single UV island. Note in the example below the interior walls unwrap as 2 UV islands, main interior walls and interior walls of the elevator space.

 

As you can hopefully see its all about marking seams, and editing the Uv islands.

Have a look at my post in the following link of how to edit the UV islands. This is only a single material Upper and lower interior walls but its the same process for your 5 materials. Unwrap everything in one go, orientate the UV islands correctly then scale them all up together. Yes the UV islands have all been scaled up so that they extend well beyond the UV space but this is not a problem because we are not baking textures we are going to apply seamless textures to the model when rezzed in world.

 

The screenshot below shows where the single vertical UV seam is placed for the outer walls. We mark seams for the rest of the model in such a way that each material unwraps as a single UV island:

 

When finished your UV's should look something like in the gif below. Selecting by material to show the UV's of that material and at the end selecting all 3 material together to show how the stacked materials UV's look in the UV editor:

 

and this is how they look when a test grid image texture is applied to each material :

 

If the above all sounds too complicated I would suggest you take a step back and  create  a very simple rectangular room, no windows, no doorways and experiment with that so that you have  exterior walls, interior walls and floor all assigned there own material, all UV unwrapped together, all orientated correctly and all scaled up together in such a way that the top of each walls UV's extend up to Y = 1 in the UV space.  Import into SL and apply some seamless tileable textures.

 

If you want to take a closer look to see where I have placed  UV seams in my model then you can download the .blend file from here :   https://file.io/vEnCtPXUC9QA

 

 

 

 

[Mesh and Li]

19 hours ago, vanettda Lassard said:

the simplified PHYS could be lower but it fits within my house needs. So you are saying that the PHYS model is causing the issue? I've had more complex PHYS files and never had this problem.

The final Land Impact cost will be the equal to the rounded up value of either the Download cost or the Physics cost, whichever is the highest.

 

If you upload with the Firestorm viewer you can check the Physics costs of your model before bringing it into SL.

At the bottom of the upload window  there is a little Physics cost panel.

• Base Hull  =  the physics cost when the Physics Shape Type is left at the default Convex Hull.
• Mesh  =  the physics cost when the physics model was not Analyzed in the mesh uploader (for Triangle based Physics) and the Physics shape Type is set to Prim.
• Analyzed  =  the physics cost when the physics model was Analyzed in the mesh uploader and the Physics Shape Type set to prim. (Analysing  converts the physics model uploaded in Step 1 of the Physics tab into a collection of convex hulls).

As a general rule, to reduce the Physics cost increase the average size of the triangles in the Physics mesh. This can be done, as Wolfie has already explained by reducing the complexity of the geometry and removing any small thin triangles (quads).

In the example below the physics model was not analysed (has a triangle count of 78). The Download cost = 1.835 and the Physics cost (Mesh) will be 0.5 when rezzed and set to Prim. LI will be 2 when rezzed.

 

Check the download and physics cost when reszzed by clicking on the more info text in the edit floater :

 

Below is an example of  an Analyzed physics mesh. Analysing created a collection of 19 hulls which when the model is rezzed in-world and set to Physics Shape Type Prim would give a physics cost of 7, (6.92 round up). Each of these physics hulls usually costs 0.36,     (19 x 0.36 = 6.84). :

 

 

 

 

[Trying to bake normals from the body and create body mods for ebody reborn]

 

 

4 hours ago, arton Rotaru said:

1) Normal maps that are uploaded as a GLTF file will use lossless compression. Hence we don't suffer from lossy compression artifacts on those.

2) To achieve the synced workflow the mesh will have to be uploaded using the GLTF viewer on a GLTF region.
in the past, meshes were stored internally packed into a unit cube. Tangents are generated on the fly in the viewer, but they were generated from that internal unit cube scale.
Means, if the mesh doesn't have a cubic shape to begin with, the tangents were generated wrongly. To correct that a change to the mesh asset format was necessary to store the original scale along with the mesh. This leads to slightly higher land impact because more data is stored.

I couldn't go to bed without trying this

I uploaded the mesh using the SL PBR viewer in a PBR (glTF) region and uploaded textures using Blender's glTF 2.0 exporter.

...... and ................... if I am not mistaken .........no "seams" ! !  

[Trying to bake normals from the body and create body mods for ebody reborn]

3 hours ago, OptimoMaximo said:

This happens because the two areas you're baking differ in their tangent space, therefore the normals *look* like they create seams, and visually do, but for the purpose of modifying the normals at the pixel level during rendering, they're correct.

@OptimoMaximo Thanks for trying to explain this. I need to spend a some more time investigating vertex normal space and why the  UV layout effects normal maps .......

 

3 hours ago, OptimoMaximo said:

Why do they have different tangents? Well, because those derive from a few factors, namely edge orientations in 3d space, edge orientation in the uv 2d space, connected faces areas and 3d world orientation. All these factor into the calculations involved for translating the surface detail from the high poly into pixel encoded normal data.

But for now I have one simple question : Are you saying that for an SL avatar mesh that is  using normal maps to add detail like Pixelberry's example, "seams" are inevitable because the UV mapping (seams and island placements and orientation in the UV space) are fixed. ? 

And these 2 bug reports are they therefore not fixable because they aren't bugs at all ?

https://jira.secondlife.com/browse/BUG-227448

https://jira.secondlife.com/browse/BUG-5975

Not even in the new PBR viewer?

 

I don't find any seams when viewed in Blender :

 

but when rezzed in SL using the standard SL viewer  with a skin texture and normal maps the seams are very noticeable:

 

The seams are less noticeable  when using the SL pbr viewer :

 

I'm guessing this is because the SL PBR viewer is using Mikkelsen Tangent Space ?   : 

https://wiki.secondlife.com/wiki/PBR_Materials

 

Which is,  I read somewhere  what Blender also uses. A secondary question follows :  Why don't we see the "seams" in Blender? (Smile because I just know that I am not going to understand the answer) .

 

[Building Buildings]

 

Tip: while creating objects that require alignment, such as the levels (floors)  of your high-rise building, avoid using arbitrary lengths like 7.136m. Instead, opt for precise measurements, like exactly 7.00m  or 7.1m. the use of one decimal place is ok but not more.  Aligning large objects with irregular bounding box measurements can be a pain .

20 hours ago, IvyTechEngineer said:

Here is something I would like to use for each floor. 

100 Vertices

200 Tris

LI 2.279

Any idea how much land impact would it be if I built 71 floors?

I think you meant 17 and not 71 floors lol .

As Chic says; "testing testing testing"

I did 2 tests, one uploading a single floor level and a second uploading which combined 4 levels( floors) into one object.

I was going to a test with having the exterior walls as one object and all the inside walls and floors as a second object but after seeing the results of the other two tests I didn't think there was much to be gained from doing that.

First the single floor object:

 

Spiral stairs in such a tall building would be terrible for an avatar to negotiate, go for an elevator, teleport system, internal ramp or wide internal stairs connecting each floor .

For the Medium Lod model we only need to create something to represent the outer walls. For the inside only the high Lod model will ever be seen so no need to create anything for the inside.

All Lod models need to contain the same list of materials. The High Lod model has 5 materials assigned to its faces so this Medium Lod model also has to have the same 5 materials assigned. One material is already assigned to the outer walls that leaves the other 4 and for those we create 4 extra triangles somewhere in the medium Lod model that wont be seen, and assigned each one of the 4 unassigned materials. ( but any ways for this example  model it has already been assumed that nothing on the inside lower than the High Lod will ever be seen ). This only applies if you are using the SL viewer when uploading. If you are using the Firestorm viewer then you don't need to worry about adding the 4 extra triangles and assigning them the 4 unused materials. No idea why I had forgotten that Beq, a firestorm dev, fixed this issue a couple of years ago. Thankyou Beq 

see Beq's Blog here :  https://beqsother.blogspot.com/2021/06/taming-mesh-uploader-improved-workflow.html

and here :  https://beqsother.blogspot.com/2021/06/summarising-next-improvements-to.html

 

For Physics..... not a lot to say except that as the inner barrier wall is only 1meter high in the High Lod model if we made the collision surfaces for this wall the same height it may be a little too low to prevent an avatar falling out over it so the physics "walls" for this barrier were made to be 1.4m high.

Uploading......  the Low and Lowest Lod slots are set to use the Use LoD above . That's to say they both will be using the Medium Lod.

 

When rezzed the LI for this single floor level object was just a little lower than yours :

 

and when stacked one above the other, 16 high the LI was 30. The missing "17th" floor would be the ground level floor, the floor with the door way opening in the outside wall to allow access to the elevator at ground level. So add and extra 1.5 LI for that.

 

Test 2 was 4 floors combined in one object :

 

 

Rezzed and with Physics Shape Type set to Prim; the LI per Floor level was better:

 

 

So the answer to your question is, it depends :

With one floor per object the 16 floor building was 30LI.

When 4 floors per object the 16 floor building LI was 20LI.  with the added bonus of having a lot less objects to align  

"Testing testing testing" 

 

 

[Trying to bake normals from the body and create body mods for ebody reborn]

 

6 hours ago, PixelBerry said:

I noticed that there is a seam where the upper and lower body connects on my normal map, is there a way to fix that other than with paint mode?

I tried baking the upper and lower body normal maps: at at first I was also getting seams. Not sure what I did differently but baking a second and third time for some reasons there were no longer any seams visible when the upper and lower body normal maps were applied and viewed in Blender.

Can you confirm that for both the high poly and low poly models the upper and lower body parts were joined together properly and not two separate meshes with overlapping vertices at the waist.

 

Are you baking both upper and lower normal maps together at the same time ?

That's to say the low poly model has 2 materials assigned to it, in my example named Torso and Lower, :

 

With the image textures selected in each of these materials, when baking high to low both upper and lower normal maps are baked together :

 

When in material preview I am not seeing any seams where upper and lower parts meet :

 

and in-world :

 

Avater mesh used in above examples is the Ruth2 v4 model from https://github.com/RuthAndRoth/Ruth2

 

[Trying to bake normals from the body and create body mods for ebody reborn]

Fix in Gimp is not a bad idea.

Instead of increasing the Extrusion value there is an other option which can give better results and that's to use a cage.

A cage is a copy of the low poly model that has been scaled up (inflated) so that it completely covers the high poly model. and it is this inflated version that is used to cast the rays that search for the High poly mesh.

I think it is quite well explained in this video :

 

Its a Blender 2.8 video but the principals stay the same only the bake normals panel is slightly different now in Blender 3.6

If you decide to try this method I would suggest you  use the Shift key while scaling the cage mesh (this is mentioned in the video), (Alt + S) (its the Fatten tool in Blender) and keep an eye on the splayed fingers while doing this scaling. You don't want the fingers of the cage mesh to start overlapping because this will cause more issues. Scale the cage up very slowly. 

 

[Trying to bake normals from the body and create body mods for ebody reborn]

The "yellow" indicates that you need to increase the Extrusion value a little. This increase the ray distance that are sent out from the low poly model to "search" for the high poly. (think I got that right )    You find this in the Bake panel when Selected to Active is enabled > Extrusion.

You need to do some tests to find the correct Extrusion distance by increasing the value little by little until those yellow artefacts disappear. Too much and it may cause other yellow bits to appear where the fingers are.

see image below:

[Trying to bake normals from the body and create body mods for ebody reborn]

35 minutes ago, PixelBerry said:

No, I'm not baking onto a low poly mesh, I'm trying to create body materials with this body sculpt, so making a normal map per se. Not sure if I'm explaining it right.

 

17 hours ago, PixelBerry said:

I recently got both mesh and skin ebody dev kits, I'm a beginner in blender that have a lot to learn. I'm trying to make body materials by sculpting and then baking the normals from the body

So, using the sculpt tools, you have added details to the default ebody mesh with the intention of baking out a normal map and then using this normal map on a default ebody avatar mesh ?

If that is the case then all you need to do is  add a default ebody mesh to the scene, this will be the "low poly mesh" and the ebody mesh that you have sculpted added details to becomes the "high poly mesh".

Now you can bake high to low   or not ?

 

[Trying to bake normals from the body and create body mods for ebody reborn]

Are you not trying to bake the details from a high poly mesh to a low poly mesh ?

If so where is your low poly mesh?

[Trying to bake normals from the body and create body mods for ebody reborn]

You can get that dark blue type normal map bake if you have assigned the high poly mesh the same material as the low poly mesh and in the Image texture you're baking to you has the Color Space set to sRGB. 

 

Example:

Low poly mesh with Torso material applied and Color Space of the blank image texture that is to be baked to set to sRGB. This image texture is selected ready to be baked to :

 

The high poly mesh has been assigned the same material (Torso) as the low poly mesh :

 

bake result :

 

Next a normal bake with no material assigned to the high poly mesh but Color Space still set to sRGB:

 

Bake result :

 

And the result of this normal map when used on the low poly mesh :

Finally the correct normal map bake with no material assigned to the high poly mesh and the Color Space set to Non Color:

 

The correctly baked normal map used applied to the low poly mesh:

 

TLDR : check that the high poly mesh is not using the same material as the low poly mesh and set Color Space to Non Color data.

 

[PBR is coming...]

3 hours ago, Lelani Carver said:

I fumbled around trying to get it downloaded, I installed 7zip to open it, not sure of next step. I’m on Windows 10.

1. Create a new folder somewhere (on desktop) and name it something like Optimo's ORM packer.
2. Drag the downloaded file into this folder.
3. Open the folder then right click on the file SL_ORM_Packer.7z  to open the Open with pop-up menu and from the options choose 7-zip  >  Extract Here . This will unzip the files into this same folder.
4. After extraction there will be 4 new files in the folder. The one we want is the file with the .exe extension, (the executable file). Double click on this file and it will open Otimo's  ORM Texture Packer. (or right click on the file and choose the Open option.)

 

 

[CREATION BLENDER]

Hi

Peut-etre vous trouverez votre bonheur ici :    https://www.avalab.org/avatar-workbench/

Avalab's Bento Female.

 

[Building Buildings]

On 9/21/2023 at 10:03 PM, IvyTechEngineer said:

It was probably one of the first things I build. I built it in SL and in Solidworks. I just downloaded both DAE files and the sloppy prim sm house.dae model has 984 tris. While the the Solidworks small house was only had 188 tris. 

Not sure if I am doing something wrong but I thought the SL built model would have fewer tris. 

The reason why the exported prim build has a high triangle count is because a simple prim cube is made up of 48 triangles.

The tri count can be reduced to 12 triangles if, before exporting from SL, you reduce the LOD Factor in the Firestorm viewer to 0.000. (or zoom way way out from the prim before selecting and exporting).

 

Export of a prim cube from SL with the LOD Factor set to 2.000 :

 

and imported into Blender, (note the high vertex count because each side of the cube is separated from the others) :

 

With the LOD Factor set to 0.000 :

 

and imported into Blender :

 

On the other hand your Chic building created in Solidworks at 188 triangles sounds very efficient. My Chic Build built in Blender comes in at similar number of tris, 198 :

 

It  would be interesting to see a screen-shot of the Solidworks build when imported into Blender in edit mode.

 

On 9/21/2023 at 10:03 PM, IvyTechEngineer said:

Also, when I downloaded the models using Firestorm is there a way to also get the physics model?

Only if you create it with prims first, (a simplified version of the visual building, for example no window openings in the walls) export from SL and bring into Blender to do some editing.

When importing the build back to SL, In Step 1: of the Physics tab of the mesh uploader, load up this physics build and in Step 2: hit the Analyze button, as explained in Chic's video.....

[Mesh Terrain Attempt 2 - Z Island]

2 hours ago, Dominic Damiano said:

Did you apply the texture in world after import? I was trying to bake the texture in Blender but I would end up with a white surface.

Yes I applied one of the image textures that you supplied in your first post then set the X and Y scale to 5 . 

Baking out a texture in Blender for such large objects as these 2 island parts would not be a good idea. The baked texture (1024 x 1024) when applied to such a large area in-world would look very pixelated (blurred). For terrains best is a repeating seamless texture.

 

[Mesh Terrain Attempt 2 - Z Island]

Continued from above....

Last thing to do is rezz our Island and in the build floater Features tab > set the Physics Shape Type to Prim:  Prim here means we want to use the mesh model we assigned in the Physics tab of the mesh Uploader instead of the default Convex Hull physics collision shape:

 

If you would like a copy of my modified Island .blender file just let me know here.

good luck lol ...............

[Mesh Terrain Attempt 2 - Z Island]

Continued...............

Filling in the top faces of the island.

In Top Orthographic view  (numpad 7) select vertices along the top edge ring > E to extrude followed by RMB (Right Mouse Button).  RMB will validate the extrusion but not move the extruded vertices. Then S to scale, move mouse so that the new extruded vertices are scaled in towards the interior of the island, LMB to validate followed by M to open merge menu and choose the At Center option.

So its : select vertices > E RMB > S LMB > M > At Center. see gif below :

 

We need now to check that the top surface of the island is perfectly flat.

To do this, Top orthographic view > Face select mode > C to activate the circular select tool and run it over the top faces. When they are all selected we can scale them along the Z axis with a scale factor of 0 (zero). S > Z > 0 validate.

Lastly we select all of the island and set the faces to use Smooth Shading.  see gif below :

 

Before separating the island into 2 parts we should UV unwrap it first :

 

To split the island into 2 separate objects, select one half then hit the P key and choose the Selection option :

 

 

We now have 2 separate objects ready to export and upload to SL :

 

In the Collada export window > Operator Presets choose the sl+open sim static option :

 

Now we have one .dae file containing 2 objects ready to upload to SL.

 

In the SL or Firsestorm viewer Build > Upload > Mesh Model and select our Island.dae file.

Note that there is a visible "seam" where the 2 parts of the island meet. To me this is not very obvious for these particular objects when rezzed and a texture applied inworld but would be for something like 2 halves of a sphere. (or for example the neck  body border of an avatar where the head mesh object joins the upper torso mesh object) This "seam" can be illuminated in Blender before exporting by using a Normal Edit modifier or Data transfer modifier. So if this "seam" does appear obvious on your island where the 2 parts meet then let me know and I will explain how to fix it later.

Next thing to do is tell the SL mesh uploader what to use for the collision surfaces of our island.

Open the Physics tab and in Step 1: Pick a physics model:  choose the High option. (High here means to use the same model for physics as we use for the High Lod model in the previous step, our visual model).

Don't touch any of the other options in this Physics window. When ready hit the Calculate weights and fees button then Upload.

 

Reached the  limit again for total file size for one post so will continue below ...........

 

[Mesh Terrain Attempt 2 - Z Island]

 

15 hours ago, Dominic Damiano said:

or do another step by step to go from start to finish in Blender?

Hmmmm ....

OK,  going for a low LI cost would mean keeping the triangle count as low as possible. The top faces of your island are one flat surface so this will help a lot.

The following may be too low poly for you but you can always add more geometry baring in mind that for such a large object it is the number of triangles in the visual mesh that will adversely effect the Download cost and it is the size/shape of the triangles in the model that will be used for the physics (collision) surfaces that will effect the Physics cost. Large triangles in the physics model will lower the Physics cost, small thin triangles will increase the Physics cost. We will be using the same mesh objects for the physics as we will  for the visual (High Lod) objects.

To conform with the SL 64m max size limit the 96 x 64 x 2m island will be split into two separate objects before uploading.

 

Note that the following steps 1 to 5 can be ignored if you already have access to the edge ring of vertices that make up the outline shape of the island.

 

Starting with the island that you have provided :

 

To get the edge ring of vertices for the shape of the island :   in Bottom orthographic view select the faces that make up the underside of the island:

 

Next, with those underside faces selected,   invert the selection with the Ctrl I keys then X (delete menu)> Faces (to delete the selected faces) :

 

We next convert these remaining underside faces from being many triangles to a single ngon face.

Select all the remaining geometry : Mesh > Clean up > Limited Dissolve :

 

 and finally we delete the ngon face leaving only the edge ring of vertices :

 

Now we are ready to rebuild the island

Start by selecting the edge ring of vertices, and extruding them up along the Z axis for say 2meters :

 

Before continuing it is important that we recalculate the normals so that all the face normals are correctly pointing outwards. With all selected, Shft N will Recalculate Normals Outside.

 

Now we scale inwards the top edge ring of vertices  using Alt S. (Alt S = scale along local normals which is "shrinking or fattening" depending on the direction the mouse is moved ) :

 

Next we can  start to optimise the geometry by merging some of the neighbouring vertices along the top edge ring. Slect 2 or 3 vertices > M key to open Merge menu and choose the At Center option. Doing this will reduce the final triangle count of the island.

Be careful when doing this we don't want to change the shape of the slope to much ! Doing this on the straight edges and on the inner concave curves works ok but not the inner convex curves.  See gif below:

 

Reached the max limit for total image size for one post so will continue in the next

 

 

[Modifying mesh prebuilts changes physics model in unexpected ways. Please explain!]

 

 

On 8/27/2023 at 4:29 PM, Thecla said:

What is happening here? It's more that I want to understand the principles and practical aspect than finding a solution, although perhaps a better conception of what is going on will allow me to find workarounds

Perhaps the best single tool to trouble shoot physics problems like that is the View Physics option in the Firestorm > Build floater > Features panel > Eye icon to the right of the Physics Shape Type drop-down.

With this enabled you should be better abled to find what is blocking any doorways etc.

For an object consisting of a single mesh object then it is not difficult.

 

Enable the view physics option (eye icon) and the physics/collision surfaces of the selected object will be displayed in blue :

If this mesh object was set to use the Physics Shape Type option Convex Hull then there would be no openings in the physics shape and an avatar would be unable to enter the building.  (For Convex Hull imagine the object wrapped in cling film).

 

For your more complicated building consisting of a link set of  many mesh parts then its a little more complicated. Some parts may have been uploaded with there own dedicated physics mesh like in the example above but others will have been uploaded without having any specific physics model assigned to them when uploading to SL. These parts may have been been assigned a Physics Shape Type: None after uploading and rely on a completely separate mesh object (or even SL prims) for its collision surfaces.

This physics mesh object will have been assigned a physics mesh to use for collision surfaces at the time of uploading into SL then set to use the Physics Shape Type: Prim.  (Here using this Prim option is telling the viewer to use the physics mesh that was assigned in the mesh uploader as collision surfaces.)This physics mesh object will be set to 100% transparent.

(Note; This single physics mesh object could have several other mesh objects (set to None) in the link-set relying on it for their collision surfaces.)

Example below is the same building but uploaded as 3 different mesh objects, Outside_Walls, Inside_Walls and Physics.

 

If for any reason one or more of the objects has its Physics Shape Type set to Convex Hull then all openings will be blocked :

 

 

So to trouble shoot,  enable the View physics tool to see how the opening is blocked, then with Edit linked checked, run through the Link set until you have that part selected  and then check its Physics Shape Type status.

 

[Building Buildings]

On 8/22/2023 at 3:16 PM, IvyTechEngineer said:

Also, at one time some one said you could have up to 8 materials for an object. How does that work? 

Yes max 8 material slots per object.

All you need to do to assign faces of the mesh to a new materials is:

1. Add the new materials to the list of materials using the little + icon in the Material Properties panel.
2. Give the new materials an appropriate name.
3. In Edit mode select the faces of the object that you want to use the new material and hit the Assign button.
4. Repeat for any other faces that require a different material.

 

When UV unwrapping the object you can

• select all and UV unwrap. this will result in all the material faces being unwrapped to a single UV space.
• or select one material and UV unwrap. This result in this one material having its own UV space. Then select the nest materials faces and Unwrap, resulting in anothe UV space for this material.

So an object can me mapped to a single UV space using max of one 1024² image texture or each material mapped to its own UV space which could mean the same object could be textured using up to 8 different 1024² image textures.

[Building Buildings]

On 8/22/2023 at 3:16 PM, IvyTechEngineer said:

Typically I do a Smart UV Project unwrap on the object and add an image as a texture and then in Texture Paint mode use the Image Editor and then I can paint on either the object or the uv map.

 

I mostly mark seams then use the basic UV unwrap and edit the resulting islands.

But I have never attempted to texture stalactites/stalagmites before . Best is use which ever method works best for you. 

 

Texture with horizontal banding. (A greyscale image can be tinted in-world to match the colour of the cave roof.) :

For a stalactite which sometimes seems to have horizontal streaks, (see screenshot above) I would find a texture with a similar horizontal banding and then UV unwrap and edit the UV's to align with the texture :

1. Mark a single longitudinal UV seam.
2. Select all and U > Unwrap.
3. In the UV editor > rotate UV island to be vertical.
4. Select the center vertical edge loop and align its vertices to the X axis. RMB to open the UV Context Menu and choose the Align X option.
5. Repeat for all the Horizontal edge loops in the UV island, RMB > Align to Y
6. Check it with the texture.

 

This is only one stalactite but in reality the 3 versions of the stalactites/stalagmites (see previous post) would be UV unwrapped together then all other stalactites would be duplicated from them and edited in the 3D viewer to have slightly different shapes. Duplicating after the UV unwrap and edit   would mean the new modified stalactites would not need UV unwrapping / editing again.

When finished editing the Uv's select the islands and Pin them using the P key. This will prevent them getting accidentally UV unwrapped (altered)  if, later you are unwrapping some other part.

P to Pin.

Alt P to Unpin.

A quick way to add a little more detail to the texture is to use it in combination with a normal map. For the above example I used https://cpetry.github.io/NormalMap-Online/  to convert the greyscale texture to a Normal map. There are many other available online.

 

[Building Buildings]

Suggestions for creating simple stalactites and stalagmites:

Get yourself some reference images. Stalagmites tend to be very stunted shapes compared to the longer stalactites.

Create the stalactites and stalagmites in pairs. The drip from the stalactite falls directly on the stalagmite below it so keep them on the same centers.

Start with a single circle of 6 to 8 vertices. The fewer vertices will make editing simpler.

Duplicate this circle > extrude down to form a cylinder (this is the base mesh for the stalactite) Duplicate the lower edge ring of this cylinder and drag it down to form the base of the stalagmite.

The rest is just editing these 2 base meshes to create 3 or 4 versions of each pair of stalactite/stalagmites and then arranging them as required. See screenshot below. :