House architecture problems!

[Ayumi Dagostino]

Hi there,

I am extremely new to building in Second Life in general, nevermind mesh, so it's probably not too much of a surprise that I'm running into big issues with my current project. My partner and I have rented a small apartment in an RP sim. We're able to rez objects inside without issue but we can't edit the internal walls to suit our tastes or anything like that. So what I wanted to do essentially is to build my own wallpaper onto the existing walls. I've been able to do this fine using prims and it looks quite good in-game but the problem is that we have a limit on how many prims we can rez inside the apartment (75), so all of my little wallpaper prims amount to 19 prims in total, which is bad! My plan was then to convert the wallpaper prims into one big mesh by exporting the prims as collada and playing about with it in Blender a little bit.

I did that to the best of my (limited) ability, cleaning up the mesh a little bit and uploading it to SL, this cut the land impact down from 19 to 3, which was definitely good. But I have two issues. Firstly, I can't seem to get the physics working properly with the architecture, namely you cant get through either of the two doors or walk about inside. I've tried playing about with the physics sliders several times over on the test grid to try and get it working but at the moment the only thing that seems to work is making the object phantom. Which isn't ideal because then you can just walk through some of the additional walls that we added to the apartment!

The second issue is that the mesh once imported is actually bigger than the prim version despite the mesh being constructed from the exported prim data. I'm not sure how to fix this but it's a big issue because we need the surfaces to be pretty much identical to the current prim version so that it fits perfectly to the walls. That was the main reason why I constructed it in-world with prims first, so we could get the perfect fit.

I've attached a screenshot below so you can see the size differences between the two buildings. Ignore the external roughness, it cant be seen normally since most of the 'walls' are just internal surfaces rather than true walls. The pre-existing apartment walls cover the outsides. 

Screenshot: http://i58.tinypic.com/2s0bswo.png 

I'd love some help to get this working properly, because customising the walls would be lovely, the current wallpaper is.. not pretty and doesn't fit the colour scheme of our furniture. I've seen another person nearby having done a lovely job of making custom walls for their apartment and they managed to get the entire mesh down to only 1 land impact, which I'd love to know how to do. Help me, mesh gurus! <3

[Astrid Kaufmat]

Hi, Ayumi.

The second iussue is probably could be matter of your exporter options:try to use the same meter units you used for building in your exporter options.

(Only in case you don't need extreme precision and in case you can easy handle it, you could resize it in world using the white handles to scale it while yo edit)

The other sounds like a physic shape thing.To walk through a mesh it should be set prim not convex hull. if you uploaded your mesh together with its physic you then have the option to set it as prim.

About the weight remember that it could depend on what you used as physic shape. The uploader shows you the convex hull weight different from prim.Upload and see , this is why opengrid or betagrid comes handy.

you could also use a decomposed shape using the analize button in your uploader and its options.remember in that case also to use solid which is for shapes like buildings.

Another alternative would be to make yourwalls physics with inworld prims setting the mesh physic shape to none and use linked prims as shape.

I leave you also some links that you could find useful just in case

http://wiki.secondlife.com/wiki/Mesh/Decomposing_a_mesh_for_physics_shape

http://wiki.secondlife.com/wiki/Physics_Optimization

http://wiki.secondlife.com/wiki/Making_Mesh_Physics

 

[Ayumi Dagostino]

Thank you for the help! In regards to the physics on the structure, I've actually tried setting them to 'prim' instead of 'convex hull', but that didn't seem to make a great deal of difference for some reason? 

[Kwakkelde Kwak]

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Ayumi Dagostino wrote:

I've seen another person nearby having done a lovely job of making custom walls for their apartment and they managed to get the entire mesh down to only 1 land impact, which I'd love to know how to do. Help me, mesh gurus! <3

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Here in the forum we can guess and guide, but it seems the answer is right in front of you.

Just edit the 1 LI object you mentioned to find out who owns it, then contact the owner. If you have the same building, that person might even give or sell you the object.

btw, if you use "wallpaper", I would link the object to something very simple, like a prim box or even a single mesh triangle or even better to some (unscripted) piece of furniture. If that simple object is the root/parent, you can set the physics for your wallpaper to "none".

[Drongle McMahon]

Here are two main alternative ways of making a cimbined wallpaper+physics shape. I hope this is something like your building. I have ignored the floors, assuming you are happy with thise as they are. For now, I'm also assuming the wallpaper is tyhe same throughout. In Blender, on the top left is a solid wall mesh, with the number of triangles minimised. Importing this as the physics and doing Analyze (solid) pruduces 16 hulls. The Prim-type physics weight inworld is 5.8, and that becomes the LI.

The mesh on the right has single plane walls with. It's basically two boxes with the required cutouts, again manipulated to minimise the triangle count. Note, however, that the normals are flipped to face inwards where the wallpaper has to be visible from. Also, that bthere are no expensive narrow faces anywhere connecting the edges of the walls, just the main faces. This is uploaded as the physics mesh without Analyze, producing a triangle-based shape with 56 triangles[1]. The inworld Prim-type physics weight is 0.7. So the LI is just 1[2].

From that result, it looks like the triangle-based shape may be the best option for this kind and size of build. It can be imported using the same mesh as high LOD and physics. That has an LI of 1. The download weight is 0.1.

The bottom of the picture shows the two models inworld, blue for triangle-based and red for Analyzed. In the middle, you can see how the triangle-based shape will fit into the house.



If you need different patterns on different walls, you can use different materials, but that will require the use of more smaller triangles, which will increase the physics weight. To make the fitting easier, you could even make each room a different mesh, so that the imported model is a linkset. Then you can stretch each independently to fit it to the existing walls. Agian, this will increase the physics weight, and the LI will be a minimum of 0.5 (server weight) per room. Something in between, like making the two boxes here as separate mesh objects, migh be the best compromise.

While watching me test these, Aquila suggested that you could save physics weight by usihng the whole mesh for the visble mesh, but just the additional walls in the physics mesh, relying on the physics of the existing walls where that is satisfactory. This could save a lot of weight. The only thinh to remember is that you must make the physics mesh fit the same bounding box as the visible mesh (otherwise the uploader stretches it to fit). So you might have to add a few extra walls to ensure that.

Notes:
[1] This can be reduced further to 36, by separating pieces to avoid triangulation.
[2] This is with the design size of 11.8x10x10m. Triangle based weights get larger as the triangles get smaller.
[3] Triangle-based weights are unpredictably variable, depending on the order of triangles or quads in the collada file. For example, the 36-triangle version had weights from 0.5 to 1.5 in a sample of five different triangle orders.

[LepreKhaun]

1.) Set your mesh to phantom. It doesn't need to be anything else to show a texture.

2.) Scale your mesh to fit by making certain you are using only the interior faces of the prims. Use up to eight materials to make faces and UV map everything in Blender. Since these are interior surfaces, break your LoD's down accordingly (they won't be seen at a distance, in other words!).

[Ayumi Dagostino]

Thank you so much for all of your help thus far! I've been very busy this past weekend so I haven't had a chance to try out the advice yet, but hopefully I'll have a shot at it during the week. 

Drongle, that was a very detailed walkthrough you gave me, although I must admit that being the newbie I am, some of it went over my head a bit! When you were putting that internal architecture together, did you model it all from scratch in Blender itself? I think I'd be able to do that as well, but right now I've been exporting prims in Collada form into Blender so that I have (supposedly) the right dimensions to fit the existing structure perfectly. However, it still came out larger when I imported it, so I'm not sure that strategy was working. Do you have any advice on how I could model the internal walls in such a way as to make sure they'd fit with the existing space I have to work with?

The way the apartment is set up when you rent it is basically a two-floored building with one room on each floor and existing walls/floors, all of which are uneditable by the tenant, which is why I'm trying to build my own walls and floors to essentially go over the default ones, so I need to make sure that they clamp on perfectly to the existing walls without clipping or taking up unnecessary space, since the space is already very limited in this apartment (It was cheap! And it's in a fairly high pop roleplay sim). 

[Drongle McMahon]

I don't know how the prim export dimensions are done. S I can't comment on how to make them fit better. You can always stretch the whole mesh after you import it, which would deal with overall errors in the dimensions, but not with relative errors, foe example in the locations of inner walls. The models I made were fron scratch in Blender. To make them fit, you could use the exported models as a guide template, but if its dimensions are wrong, that won't be any better, So the best way to do it would be to make accurate measurements inworld (stretch a cube to the dimension and read the dimension from the edir dialog), and build to those. Turn on edge length display in Blender to check and adjust them. As /i mentioned, making separate meshes for each room would simplify fitting, as thery can be individually stretched to fit, but would cost more in nphysics weight. The way to do that would be to make them separate objects in Blender and import together. Trhat will make a linkset.

As LeprKhaun pointed out, if you already have the extra walls as prims, then you don't really need the wallpaper to have physics if it fits properly. So you should be able to make meshes with inward-facing normals, like the triangle-based one but simpler, maybe just a cube for each room. Put the texture on those and just stretcvh to fit. At the extreme, you could use a separate flat plane object for each wall, with required cutouts for doors etc. Each simple mesh like this, when they are linked in a linkset, would cost 0.5 LI. Instead of using phantom, which still taxes the physics engine, they should have their physics shape type set to "None" after they are linked to one of you extra wall prims which remains as the root of the linkset (last selected before linking).

[Aquila Kytori]

Hi

One thing I don't understand is why the Prim build that you exported to your hard drive then imported into Blender is not exactly the same size as when rezzed in world ?

Using the Singularity viewer I tried exporting  a 10 meter cube in both .dae and .obj formats from SL and opening in Blender.

Then exporting each as seperate .dae files and imported  back into SL.

When rezzed both still mesured 10 x 10 x 10 .

Has your mesh been scaled uniformally bigger or only in one or other of the axis ?

I add a couple of pics to show you a few things you should be aware of like where to enable Metric Units and edge lengths in Blender. Note one meter in Blender = precisely one meter inworld .

First the .dae cube :

 

and the .obj cube:

[Ayumi Dagostino]

It could be a problem with Firestorm's export perhaps compared to Singularity, I might try them both and compare. Otherwise maybe I did something wrong, I'm not sure, but I'll take a look! If they were exactly the same size most of my problems would be very fixable! 

[Coby Foden]

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Aquila Kytori wrote:

 

Note one meter in Blender = precisely one meter inworld.

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I can confirm this too. 1 meter in Blender = 1 meter in SL. Exactly.

I made a simple house inworld from prims. I saved the house inworld as collada file and opened in Blender (version 2.70). I checked the dimensions of the house in Blender and they were exactly the same as inworld.

 

Then I saved the the house in Blender as collada file and imported it to SL. Again checking the dimension. The imported mesh house was exactly the same size as the original prim house.

 

PS.

Firestorm 4.6.1 was used for export and import.

 

[Ayumi Dagostino]

Switching to Singularity did the trick and I've got it working now, only 0.5 land impact and fully textured, fitting nicely to the walls

Thanks for the help all!