Part of linked mesh appears invisible

[Sienia Trevellion]

In blender my mesh looks fine. When I go to upload it to second life however, a section of it appears invisible.

 

A few things:

1.) I only have 4 materials.

2.) I checked the normals on the area that appears invisible and they seemed fine. To be certain, I reversed them and tried to upload the mesh again with the same result.

3.) I have no textures applied to the mesh.

I'm not sure why this is happening but I'm thinking it's something simple I'm overlooking. Is there something I might have selected that would make this area invisible?

 

 

In blender:

 

In SL Preview:

[Drongle McMahon]

It may be too many triangles. Can you do the following on a copy - in Blender, select all and triangulate faces, then select each material and record the face count (which is now triangles) - then record the triangle count you see in the uploader. Tell us these numbers and we will see if that could be the explanation.

The uploader constructs lists of triangles for each material and starts a new secret material when it gets to 21844 triangles. So it can then see more materials than were in the collada file.  If it gets to more than 8 materials, it simply discards the rest without telling you (this is a reported bug).

[Sienia Trevellion]

Thanks Drongle, I'll take a look.

_________________________________________

 

Okay:

Material #1: Faces = 4,408

Material #2: Faces = 960

Material #3: Faces = 4,104

Material #4: Faces = 96 (this is the area that is showing invisible)

Uploader traingle count on High = 150676 (before adjusting/dropping it down at all) That seems very, very high.

Do I need to drop the detail - is this a retarded, massive amount? What I'm attempting has an area with flowers (see below) with a lot of petals, should I have built this differently? Maybe I can redo the actual collar area so that there is an edge but no inside and remove edge loops. I didn't realize it was so big - still trying to figure out how much detail is acceptable and such and am feeling like a complete noob atm.

 

[Rahkis Andel]

Do you really need the subsurf? If not for that, the mesh would be fine. With smooth shading, I doubt you'd know the difference.

Remember, this is a game, not an animation.

[Sienia Trevellion]

Good point. You know, I'm not sure...that bottom area on the collar that is scalloped or wavy, it's actually got pointed tips without adding a subsurf. Let me try to round each off and simplify it. You're making me think differently about how to model it. I'm assuming the high amount of triangles was the problem then.

[Rahkis Andel]

Yes, That's expected.

One thing you could do is apply the subsurf and manually remove all of the edges that do not define a shape that needs to be a smooth curve.

As long as it's reasonably smooth, that's enough to look good at any reasonable difference with a texture.

Just realize that the uploader starts having a panic attack at around 25k triangles (don't quote me on that). Also realize that the default avatar is around 7k triangles altogether. No single article of clothing ever needs to be more dense than an entire character model.

[Sienia Trevellion]

That's exactly what I'm doing, applied it and have been in there deleting unnecessary loops to keep that curved edge but lower the count. 25k is ridiculous and I don't ever want to be uploading things that are lagging everyone out. Thank you again for the help, this is a good one for me to learn from and think about upcoming modeling differently.

[Helium Loon]

Just looking at the pictures you included, some of those parts are patches, not triangles meshes.  You may need to convert them to regular mesh triangles.  That would also explain the difference in triangle counts.

 

[Sienia Trevellion]

I'm sorry Helium, I don't understand what you mean by patches?

[Rahkis Andel]

I think they mean quads...As opposed to tris. 4 sided polygons. I guess they are saying that you should convert to triangles, but I disagree.

Assuming you're using a recent version of Blender, the exporter automatically triangulates your mesh upon export.

[arton Rotaru]

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Sienia Trevellion wrote:

 

Uploader traingle count on High = 150676 (before adjusting/dropping it down at all) That seems very, very high.

 

 

 

 

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Just to show some examples. On that image below is what I made out of 150000 triangles. That's all HIgh LODs summarized.

[Drongle McMahon]

Material #1: Faces = 4,408; Material #2: Faces = 960; Material #3: Faces = 4,104; Material #4: Faces = 96; Uploader traingle count on High = 150676 (before adjusting/dropping it down at all) That seems very, very high.

It would appar that those are the counts before subsurf is applied. Each level of subsurf will multiply the triangle count by three or four fold. So you very quickly get excessive counts. Two levels could take this over 150,000. Try to rely on smooth shading rather than subsurf to get smoothness except at visible edges. From the 150,000 in the upload, I think this is certainly the problem. When you have one material, it gets to 174,752 before it start culling triangles, but each extra material will have a list of triangles that has unused capacity, so that the ninth pseudo-material get started earlier. That space could be could up to 20k per material. So the number you see is entirely consistent with having too may triangles.

Incidentally, flat shading will also cause multiplication of the vertices, as they have to be stored with each different normal they are used with. With smooth shading they always have the same normal in all the triangles they appear in. Highly fFragmented UV maps have similar effects. These effects can easily treble the triangle count.

[Chic Aeon]

Just wanted to say that is lovely and I hope you get the polycount down.

You know I recognized your name but had to Google you to remember why *wink*. Glad you are still with us and still working. I have your books out at MOSP in several locations. They are standing the test of time well.

Cheers.

[Sienia Trevellion]

Oh.my.god.

This is an awesome example of how incredibly, ridiculously, outrageously large the amount of triangles is on my little itty bitty thing. I'm going to take a deep breath and just realize that soon, hopefully very soon I'll get this. LOL, thank you for the example!

[Sienia Trevellion]

This is also very helpful. I think if I can adjust the way I'm going about some things I can get the counts down to reasonable, workable levels. I will probably post the count once I've reworked or rebuilt it to get feedback. I swear I'll get this someday. LOL. Thank you for your patience!

 

[Sienia Trevellion]

Aww, thank you so much, that means more than you know! I'm trying to learn mesh and really enjoying it, but I want it to not only be beautiful but functional. Pray for me. hahaha. Pray hard.

[arton Rotaru]

Just don't go mad about it. :matte-motes-big-grin: It takes some practice to get the hang of lowpoly modeling. Your first models won't be as good as your 10th model, and so on. Just keep in mind to try to achieve what you want with the least amount of polygons possible. It's challenging some times, but it makes it also more interesting.

[Sienia Trevellion]

I reworked it and was able to drop it, but not enough to be reasonable yet. I'll keep at it. These are the counts after applying a subsurf (if any), and focusing on using smooth instead. The petals are the thing that keep stumping me because they are double sided. I'm going to focus more on dropping their count next.

Material 1 (collar): 2816

Material 2 (inset fabric): 64

Material 3 (pearls): 960 - On this note, is there a way to make a smooth, low-poly sphere? I'm going to look around for info on this on blendercookie and such.

Material 4 (roses): 14676

 

I'm wondering about something. On this collar, could I delete every other row of edge loop but keep the area at the bottom so the scallop stays. Is this bad topology?

 

I know my questions end up being more like conversations but I learn a ton here. You guys rock.

 

[Rahkis Andel]

No, that isn't bad topology at all. You should delete every other edge as you are doing and it won't affect the shape much at all. It could still be improved on top of that, though. I would also like you to try something for me:

1. Enter edge selection mode.

2. Select every other two vertical edge rings (ctrl+alt+shift+rmb). In other words, select two consecutive edge rings, skip one and select two again until you make it to the other side of your object.

3. Deselect everything from the bottom two edge loops that define the wavy shape.

4. Edge collapse everything you've selected (x -> edge collapse).

5. Clean up the leftover triangles by dissolving them.

This way, you maintain the wavy shape you want, but remove the density where it isn't needed, higher up.

[Sienia Trevellion]

Ohhhhh!!!!! Yes! Okay let me try this!

[Sienia Trevellion]

Rahkis, I love you!

[Rahkis Andel]

Now you're getting it!

My only critique is that I would reccomend avoiding triangles in your working mesh. Eventually, you're entire mesh will be triangulated, and any triangles you put in yourself will not be split and may cause irregularities that can have some minor but avoidable complications.

Plus, quads are a million times easier to work with.

[Sienia Trevellion]

Oh I see what you're saying. Let me do it again and as you said, clean up the triangles. Yay! I'll post the final cleaned up version when done. You are a lifesaver and a great teacher for blender noobs

[Kwakkelde Kwak]

I might be missing something, but from a low poly point of view I would seriously prefer the triangle option over the quad option here. Also topologywise the quads aren't any better from what I can see than the triangles. Loops and rings are as distorted with the quads as they are with the tris. Purposely made tris should have better results than the ones made out of quads as far as lighting irregularities go. With the quad you don't know how things will be triangulated, with the tris you will, since they already are tris.

Enlighten me:)

[Rahkis Andel]

I think what you missed is the "Working mesh" bit. That phrase was up to interpretation, I admit.

That is to say, go ahead and triangulate your mesh before/during export, but while you are working with it, keep it to all quads.

As for why: I'm sure you already know the answer to that.