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Show Us Your Meshes!


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It's pretty high, around 30 prims right now. I need to replace single leaves with leaf clusters (fewer triangles) and provide a physics proxy.  This is still a learning process for me how to make various kinds of objects.

There two costs which are not final yet, upload cost and land cost in prims.  Rendering cost would be more like how many triangles it adds to the scene, which is about 10K at the moment.  Graphics cards have a finite speed in rendering triangles, so generally frame rate on the screen goes inversely with triangle count

UPDATE: The photo in the first post has been updated with a new leaf cluster texture.  Now is 9K triangles, and 15 prim cost.  Still needs physics proxy.

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TeapotTestPics.png

 

This isn't exactly an exciting theme, but I'm learning alot about the effects of various options such as the cost of using subsurf, etc. These teapots range from 4 prims to 9 prims in cost with some modeling refinements on the two on the bottom in green.  I started out with more ambitious plans, but  I've toned down my projects and its a better learning experience for me. In focusing on this simple object, I've also learned quite a bit  more about modeling and UV layout alternatives in Blender . Much fun.

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This is propaganda for meshes compared to sculpties. The two halves show highest and lowest LODs for a simple mesh window. It is possible to make an identical window with a sculpty, and get it textured amost as well, but that is 2048 triangles while the high LOD mesh is 62*. Then at lower LODs, we all know what happens to sculpty window frames. The best can survive one LOD step, but then... Here, the lowest LOD is just 8 triangles with an alpha texture. There is plenty of spare for extra bars before the window becomes more than one prim.

wfreg.jpg

*in case you are wondering,  high and low LOD meshes each have extra hidden faces to carry the materials used for the other LOD. That's because the uploader insists on the same number (and order) of materials. For the low LOD picture, renderVolumeLODFactor was set to 0.1.

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Nice window Drongle! I have not played much with static meshes so I hope you don't mind a couple of simple questions.

For the pane of glass and the wood textures, did you use two separate materials and then apply the textures in SL? Any problem with applying an alpha'd texture to a face created with a material? Can you set transparency in the build edit window on a face created with a material?

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Vivienne Daguerre wrote: For the pane of glass and the wood textures, did you use two separate materials and then apply the textures in SL? Any problem with applying an alpha'd texture to a face created with a material? Can you set transparency in the build edit window on a face created with a material?

Short answer : Yes, Yes. Long answer....

As this was an experiment, I had several versions designed with different things in mind. I will show you the best and, maybe, the worst.

On the left is the UV map which allows application of separate tileable textures, which is the most efficient way of getting high detail. The important thing is that the wood all runs in the same direction.

Identical parts have their UV maps superimposed to get better detail/texture size ratio. This still allows making an ambient occlusion (ao) map and overlaying it on a tiled texture to make a nice custom texture. You have to be very careful that the overlaid  parts are accurately identical for this to work, but it is very well worth the effort in reducing the required texture size.

If this were for general purpose textures only, the different shapes for the wood could be superimposed too, but that would mess up the ao. The compromise allows both techniques.

The wood is all one material. The large rectangle is the UV map for the glass, which is a separate material. This can either be an alpha texture or a solid texture with the transparency set in the edit dialog (it's the latter in the picture). The tiny rectangle is the hidden face that carries the low LOD texture in the third material. That has to be alpha as it has solid and transparent parts in one material.

wtst_uvmaps_pic.png

On the right is the UV map for a technique that allows all three materials to use the same large texture. I do not approve of this (although that is the one shown in the picture!) as it cannot be retextured (paint it or change the wood) with a simple texture, and it requires a much larger texture to obtain equivalent close-up detail.

You can see the map includes a part that is used for both the front face of the wood and the glass.The outer rectangle of this is also the UV map of the low-LOD mesh. That is how the same texture can be used for both.

The same rectangle serves for the high LOD glass with the crossbeams being covered up by the solid bars (actually that doesn't work perfectly, and in the picture shown the glass is a separate texture). At high LOD the transparency of the glass can be set in the editor with a non-alpha texture, but at low LOD, the glass would then be non-transparent. So if the low LOD glass needs to be transparent, the whole texture has to be alpha.

Here is map superimposed on a texture made for the bad UV map that was actually used only for for the wood in the pictured window. The ao for this was done after removing the glass. It would look better overlayed with one when the glass is still there, so that you would see darkness in the glass-carrying slot.

wintest_uvpic2_reduced.png

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Nice post, Drongle.

I wish expert SL users would make some tutorials focused on SL building on all this stuff, as there is so much to learn and, frankly some of it sounds a bit cryptic to me. Inworld classes would be great, too.

Well, if anyone makes some tutorials please let me know so I can add a reference to MetaLibrary.

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For completeness, here are pictures of the window mesh, both using the smaller more efficient UV map. The wood is textured with a small 256x128 texture with repeats, on the left, or with a larger 512x512 texture made by superimposing ambient occlusion onto the same texture tiled, on the right.  The ao is actually a mixture of bakes with and without the glass. This sort of frame could be distributed with the plain ao texture, so that those that know how would have the choice of using it with their chosen texture or just using that texture alone. I guess it would need a lowest LOD texture too, with a selectable area to fill with the new texture. Alternatively, it could use just the medium LOD that uses the same map as the high LOD, but that increases the prim cost to 1.4.

tstwin_pics_teak.jpg

Of course, the biggest advantage of using the simple texturing (left) is that you can use the same texture for lots of windows (and other things) with different numbers of bars etc. This can save a huge amount of texture downloading and thus minimise lag.

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Having followed the mesh forum for a little while now, I guess I should begin posting (I have questions to ask in later postings, and hopefully I can offer some helpful advice as well from my limited knowledge).

This is what I am working on while learning about SL mesh: A bootie. I still have things to learn and work out, but this is my progress so far:

MB Bootie closeup 01.jpg

(The shadows are baked-in AO textures). There is a basic leather texture (white/pale grey), but I will work on proper textures later on.

MB bootie colours.jpg

This is the same mesh, but with colours applied onto the material maps (via the edit prim settings inside of SL). I love the possibilities of materials, plus the control of UV mapping (compared to sculpties and standard prims).

And.... one more shot for vanity :smileywink:

MB Bootie closeup 02.jpg

I am grappling with the LOD issues though, when this mesh is reduced to fit an AV's foot - it breaks up terribly via the default SL LOD (due to the tiny size and heavily reduced LOD distance, as far as I can tell). I am considering cutting this mesh up into segments, in order to keep triangle counts down around the second lowest LOD level, to hopefully overcome this issue, and create a separate mesh for each segment that won't squeeze into the lowest LOD count. Not ideal, I know - although it would still be much more efficient than creating it via sculpties. (Feel free to offer alternative suggestions!)

But yah, I am very excited by the potential of mesh in SL - much greater creative freedom! :smileyvery-happy:

 

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Concerning the LOD (current situation - nothing certain). The aiutomatic LOD system will go on reducing the triangle count until each mesh is one two-sided triangle. So splitting the shoe into pieces is unlikely to help you. In fact, the smaller size will make the LOD switch even closer.

Instead, you can tell it (advanced dialog) to use less stringent LOD reduction. In fact, you can use the same mesh at all levels, if you really want to (not recommended).

The easiest way is to use the triangle limit dials. However, unless this is fo zero reduction, it will rarely give satisfactory results unless your high LOD has lots of redundant triangles.

Better is to upload your own LOD files. In the extreme, you can use the same file for all four. There is a high streaming cost penalty for this, but as shoes are to be attached and streaming cost does not matter for attachments, it would be possible.

Good practice, however, for the sake of performance, would be to provide the greates triangle reductions that are compatible with acceptable viewing at the default renderVolumeLODFactor settings.

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Thanks for the tips Drongle.... I can see your point, that the reduced segments of the shoe would make the LOD distance even smaller again.

I have yet to really properly explore all the options in mesh upload dialogue. I have previously looked at the default LOD levels on offer (first tab) and assumed the triangle counts were unable to be raised above their upper limits (ie: Medium LOD 385, Low LOD 97, Lowest 49) - and thought that I would have to squeeze my mesh into those counts for it to be accepted (hence my concept before of cutting my shoe mesh into segments). From what you have mentioned, I will explore the advanced dialogue section and see what results I can obtain (I will have a look when I get a chance to log into the test grid next time).

My mesh itself (full LOD) due to its organic shaping is relatively expensive in triangle count, although I kept it as conservative (low poly) as possible in the modeling process - from memory, the total triangle count is a fraction over 1K polys (the shoelaces are pretty expensive, although I could probably reduce this a little more; the main shoe shape itself is about 625 polys). For what it is worth, I think the prim cost was about 2.3.

I would be happy to create my own reduced LOD meshes to retain greater control over their deformation etc.

Regarding the creation of reduced LODs, I assume I would have to create relevant UV mapping and textures to go with them? (I am impressed at how the automatic LOD system is still able to map my textures to the reduced meshes). I guess in the upload section there are options for including textures for each LOD level etc.

Thanks again for your input - your advice is a big help for a learner like me :smileyhappy:

And thanks Vivienne for your comment - Glad that you like what I have come up with so far :smileyhappy:

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For now the only limit on the LOD meshes, triangle dial or file,  is that they can't have more triangles than the higher LOD. Since it is still beta, we can't guarantee that it will stay that way. I hope it does because there are many cases where reduction is harmful and/or pointless. There used to be a limit ... you had to at least halve the count per step. So you might need to be using the latest development viewer to avoid it.

The best thing is to make the UV maps for the low-LOD meshes fit the same texture as the high LOD one whenever that is possible. I do that in Blender by editing the meshes by merging vertices. This leaves some points on the UV map in the right places and you just have to move the others to close up the gaps where the deleted faces were. It is quite a lot of work though. Another way would be to make a new UV map and then edit it to male it fit the texture.

If you really need to use different textures, then they have to be different materials/faces, as the face number-texture association is shared by all the LOD meshes. That's why they must all have the same number of faces. That means you have to use hidden faces to hide the textures that are not used at a particular LOD level. For example, my windows use an alpha texture on a flat planes at lowest LODs. The high LOD meshes have a face hidden inside that has the alpha texture, and the low LOD box has hidden faces that carry the high LOD textures.

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Drongle - I downloaded the latest develpment viewer as you suggested (I was using the bog standard mesh viewer)... and yah, it has more options for LOD control as you said.

I had a quick bit of experimenting - adjusting different counts for each LOD (keeping the high and medium LOD at the actual original mesh triangle count, and reducing the low and lowest counts to varying amounts (roughly two-thirds for the low, and about half for the lowest). Seems to be a far better result this way, I am happy with how the mesh model holds its detail, even at long view distances. I could probably tweak this further with more trial and error, and will play with that later.

As it stands... the mesh cost is 23.0 .... a lot higher than the original 2.9 with default LOD settings, but I guess still far more efficient than the normal prim count / texture sets an equivalent sculpted shoe would require (although I'm no expert by any means in regards to streaming costs etc, so correct me if I am wrong in my assumption). Since this shoe is designed to be an AV attachment, I guess the prim cost isn't too major a concern; although I DO care about render cost - hopefully this is somewhat within reasonable bounds.

As a side note... the reduced LODs combined with my AO texture seems to work well in maintaining some kind of recognisable detail at distance, despite its small size (foot size), which I am very happy with.

Thanks again Drongle for setting me on the right track - now I know I am heading in a productive direction :smileyhappy:

 

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