Model Building

[ChinRey]

14 minutes ago, Aquila Kytori said:

The most common cause of this is that the object has more than one UV map. This can result in the wrong UV map being uploaded with the model.

Another possibility is that the model has a non-uniform scale. That can easily happen when you work with nurbs and it tends to mess up the UV mapping. The Blender developers even included a popup alert when you try to UV map a mesh with non-uniform scale and the never bother with adding popup alerts.

While I'm at it, the UV map here is not good by any standard. There's this myth among SL creators and many other amateur 3D modellers too that Blender is good at UV mapping. It is't, it's horribly bad at it, so if you want something decent, you have to be prepared to do a bit of manual adjustments.

But as Aquila says, you do not use a texture like this if all you want are monochrome surfaces and you certainly don't use a 1024x1024 - or even a 512x512 - for it.

 

17 minutes ago, Aquila Kytori said:

1: Don't create a texture at all.

  In Blender assign the model wire 2 materials, for example : "Plastic" and "metal". Then assign these materials to the appropriate faces of the  model. When the wire is rezzed inworld edit it and from the build floater > Texture > Select face enabled Give the plastic part a red colour the select metal part and give it a grey colour.

Advantage is: no UV unwrapping to do. Don't need to create a texture and upload it and you can change wire colours when ever you want.

This is definitely the best solution. Only, remember to set the texture to the default blank in-world too. The default blank texture is likely to be in everybody's cache and it's so small 32x32 it doesn't add any lag worth speaking of anywhere in the rendering pipeline.

19 minutes ago, Aquila Kytori said:

2: UV unwrap and create a much smaller texture.

Because you are just painting pure colours, red for plastic part and grey for metal then you could in theory have a texture size of 1 x 2 pixels.

That's an old trick commonly used by low poly games.

Keep in mind that textures will always be a little bit blurred when you upload them to SL so you need a bit more than a single pixel for each colour. 4x4 pixels pr. colour should be fine.

[IvyTechEngineer]

Thank you for the advice and help. Yes I checked and I had two UVmaps on my cables. I had always thought that to add color to an object you needed a texture. I will attempt to use your first suggested approach for assign the model wire 2 materials. Thanks

[IvyTechEngineer]

7 hours ago, Aquila Kytori said:

The most common cause of this is that the object has more than one UV map. This can result in the wrong UV map being uploaded with the model.

In Edit mode with the model selected click on the Objects Data Properties tab and then under UV maps check if there are more than one UV map listed.

If yes then you have the option to either delete the one(s) you don't want or simply make sure the one you do want is selected (active) before you export.

Don't confuse the selected/active UV map with the little camera icon. The camera icon is only for telling Blender which map to use when rendering .

In the screenshots below there are two UV maps for the model.  UVMap and UVMap001

The first image shows the correct UV map has been selected :

 

The next image shows the incorrect UV map selected  but in the 3D viewport the correct UV map is sill being used because the camera icon for the correct map is still enabled :

 

Next with the other UV maps camera icon enabled we now see the change in the 3D viewport :

 

So before exporting make sure the correct UV map is selected:

 

and in the Collada export options  > Operator presets choose  sl+open sim static.

 

On a 1204² texture you seem to be simply painting the insulating part of the wire red and the metal part grey and saving this to use on your wire inworld. ??

Ask yourself if this is a good use of resources?

what other options do you have?

1: Don't create a texture at all.

  In Blender assign the model wire 2 materials, for example : "Plastic" and "metal". Then assign these materials to the appropriate faces of the  model. When the wire is rezzed inworld edit it and from the build floater > Texture > with Select face enabled give the plastic part a red colour then select metal part and give it a grey colour.

Advantage is: no UV unwrapping to do. Don't need to create a texture and upload it and you can change the wire colours when ever you want.

2: UV unwrap and create a much smaller texture.

Because you are just painting pure colours, red for plastic part and grey for metal then you could in theory have a texture size of 1 x 2 pixels. 

In Photoshop or Gimp create a 1 x 2 pixel texture. colour one pixel red and the other grey. save and then bring into Blender as the texture for your wire.

Next in Blender...... select part of your model you want to be red and UV unwrap it ,  U > Unwrap. (No need to mark any seams). In the UV editor select the resultant UV island and scale it down to a single point using S (scale) 0 (zero). Then position the single point collapsed UV's over the red part of the texture. Repeat for the metal part of the wire. Et voila ! your wire is textured exactly the same as you have it now but instead of using a 1024² texture size (1,048576 pixels) you are using a 1 x 2 (2 pixels).

Of course you cant upload such a small texture to SL but you get the idea. Why use a texture when you can create the same effect by giving your model two materials in blender and then assign those two material faces their colour in world using the SL build floater ?

Your model your choices

 

 

 

Ok, after a little false start I have the first version, which is not exactly perfect. But I am pretty happy with what I have so far. Probably I could have done everything in Blender with the exception of maybe the scripted parts. 

[ChinRey]

29 minutes ago, IvyTechEngineer said:

...

with the exception of maybe the scripted parts.

You should have a word with Mcarp Mavendorf. He's one of SL's very best scripters, machinery like this is one of his specialities and he's always willing to help people who seriously want to improve their scripting skills. There's a good chance you'll find him at NCI Kuula and if you don't ask one of the helpers there if they've seen him.

Edited February 18, 2022 by ChinRey

[Aquila Kytori]

14 hours ago, IvyTechEngineer said:

Ok, after a little false start I have the first version, which is not exactly perfect. But I am pretty happy with what I have so far. Probably I could have done everything in Blender with the exception of maybe the scripted parts. 

Nice one !

I like to see "mechanical" machines with moving parts in SL.

[IvyTechEngineer]

After a model has been uploaded is there a way to review its tris, quads, LI, etc?  If you build it you should know these things but how would someone else know these values?

[ChinRey]

1 hour ago, IvyTechEngineer said:

After a model has been uploaded is there a way to review its tris, quads, LI, etc?

Yes. In FIrestorm you can find all of that info spread out between the build/edit and the object inspect palettes. The standard viewer displays some but not all of the info.

[IvyTechEngineer]

Thanks Chin

[IvyTechEngineer]

My impression of using Blender as a model editor recently came into question when I drew a hollow ramp in SL and saved it to my desktop. I wanted to add some architectural significance to the ramp by adding cutting out on both sides based on one of the truss designs we worked on last semester. However when I imported the dae file into Blender I was surprised some of the questionable edges I saw in edit mode in Blender.  My not cleaner geometry? 

https://www.ivytechengineering.com/SecondLife/files/ramp.dae

Thanks

[Frionil Fang]

1 hour ago, IvyTechEngineer said:

However when I imported the dae file into Blender I was surprised some of the questionable edges I saw in edit mode in Blender.

The inside is hollowed out very aggressively in the corner, to the same line as the outside surface (i.e. zero thickness). Due to inevitably limited precision of coordinates, Blender doesn't know which side to show on top in all circumstances. I'd move the inner corner to give the object proper thickness there.

[Aquila Kytori]

1 hour ago, IvyTechEngineer said:

My not cleaner geometry?

Clean up in 4 steps:

1:   Edit mode, Vertex select mode, select All and  Mesh > Clean Up > Merge by distance:

 

2: Clean Up > Degenerate Dissolve :

 

3:  Clean Up > Limited dissolve :

 

4: any remaining unwanted vertices select and Dissolve Vertices :

 

And as Frionil mentioned you will have to manually correct the zero thickness at the inner corners :

 

.blend of cleaned up ramp :  https://pasteall.org/blend/18d97a2bd9a04b9c9388040e1d28b0f5

Sometimes it just makes more sense to create from scratch in Blender !

 

Edited April 25, 2022 by Aquila Kytori

[IvyTechEngineer]

1 hour ago, Aquila Kytori said:

Clean up in 4 steps:

1:   Edit mode, Vertex select mode, select All and  Mesh > Clean Up > Merge by distance:

 

2: Clean Up > Degenerate Dissolve :

 

3:  Clean Up > Limited dissolve :

 

4: any remaining unwanted vertices select and Dissolve Vertices :

 

And as Frionil mentioned you will have to manually correct the zero thickness at the inner corners :

 

.blend of cleaned up ramp :  https://pasteall.org/blend/18d97a2bd9a04b9c9388040e1d28b0f5

Sometimes it just makes more sense to create from scratch in Blender !

 

Thanks Aquila, I agree that it is easier to draw in Blender more complex geometry but I was surprised that the downloaded SL dae file was not better. The Mesh cleanup really helped and I understand your comments about Ngons to Quads. I wonder if some of these mesh cleanups would also help me on my mountain mesh model. OBTW, when I tried the last time to use the high LOD for the physics SL said that I have some small triangles. However, when I look at the model in Blender I don't see the same mesh. Not sure why Blender and SL would have two difference geometries ...

[IvyTechEngineer]

1 hour ago, Frionil Fang said:

The inside is hollowed out very aggressively in the corner, to the same line as the outside surface (i.e. zero thickness). Due to inevitably limited precision of coordinates, Blender doesn't know which side to show on top in all circumstances. I'd move the inner corner to give the object proper thickness there.

Thanks, the hollow was set to 95 so the wall thickness would not be zero I don't think ...

[Aquila Kytori]

2 hours ago, IvyTechEngineer said:

Thanks, the hollow was set to 95 so the wall thickness would not be zero I don't think ...

 

[IvyTechEngineer]

I was able to create some new ramps with trusses that look pretty good in Blender. Need to add some materials and they should be good to use. 

Thanks 

[IvyTechEngineer]

On 2/17/2022 at 7:40 PM, IvyTechEngineer said:

Ok, after a little false start I have the first version, which is not exactly perfect. But I am pretty happy with what I have so far. Probably I could have done everything in Blender with the exception of maybe the scripted parts. 

I wanted to post the latest DC Motor model that I have created with help from Arton, Chin and Aqulia as well as some others with the scripts like Roling. It looks and works great. Thank you for all your help.

https://www.ivytechengineering.com/SecondLife/files/DCMotor.gif

 

[IvyTechEngineer]

Sorry, I have a follow-up questions about the ramp model I created. I wanted to see how it would look like in SL so I uploaded it to Opensim but it doesn't look to good. 

https://pasteall.org/blend/bcab95fb96a34d88854d97323eb3028a

Not sure why all the geometry is not visible if I am right next to it. 

Suggestions?

Maybe its a limitation with Opensim?

Thanks

[ChinRey]

4 minutes ago, IvyTechEngineer said:

Not sure why all the geometry is not visible if I am right next to it.

It's because meshes in SL and opensim don't have backfaces. So if you want a surface to be visible from both sides, you need to duplicate it and switch the normals for one of the copies.

[IvyTechEngineer]

ok, I thought it was something like that. 

Thanks

[Aquila Kytori]

41 minutes ago, IvyTechEngineer said:

Suggestions?

To see how faces only have one side work in Blender with Backface Culling enabled.

1: Change Viewport Shading to Solid.

2: Open the Shading drop-down and enable Backface Culling

 

[Aquila Kytori]

45 minutes ago, IvyTechEngineer said:

Suggestions?

To give your model some thickness add a Solidify Modifier. But not too thick otherwise it will get messed up !

[IvyTechEngineer]

3 hours ago, Aquila Kytori said:

To give your model some thickness add a Solidify Modifier. But not too thick otherwise it will get messed up !

That works, thanks. I originally drew this in Blender and thought that I could extrude a solid from a face but for some reason it creates a shell verses a extrude from the face. I can follow your suggested approach but why doesn't Blender extrude? OBTW, if I select the vertices I can do a fill and create normal faces...

[IvyTechEngineer]

When you extrude from a face and you enter a negative value it becomes an extrude cut. I believe this is what has happened to my ramp. I want the extrude to go into the model not out from the model. 

[IvyTechEngineer]

Moving on to the next piece of the puzzle I wanted to upload an Arduino Uno board that is very popular in electronics right now. We use it in many of our school projects and I wanted to upload a 1 meter version for students. I found a model on GrabCAD and downloaded it and converted it to an STL. The model has more geometry than is needed but I am not sure how to simplify some of it. 

https://pasteall.org/blend/6adef1fd1d8c4dea982090ef1b53cc42

Any suggestions?

Thanks

ivytechengineer

[IvyTechEngineer]

This model has these metrics: 

Upload Fee    37
Land Impact    27.57
Download    27.57
Physics        4.6
Server        0.5