I built a model I plan to use in my OSGrid regions. I don’t want to do a tutorial on Second Life Mesh. Gaia at Machinimatrix.org does those so much better than I would. But, I do want to pass on what I have learned without getting too techy.
I can say that mesh is working pretty well. It certainly is much easier to texture mesh than it is sculpties. One can have custom UV Maps and that is a big step up.
I also took a quick look around the ADITI Mesh Enabled Regions. I have included some images I captured.
Those that have played in the more recent Myst games (see Myst Online for the free mMOG) will recognize the type of pedestal. The ‘linking’ (like a teleport) pedestal (grass background) is made in two pieces.
I made a pedestal from prims and a sculpty (the stone floor background image) that took 11 objects. I could probably reduce that count by 1 or 2. I think if I made the mesh pedestal in the image just from prims I would need 11 or 14. There are some small beveled areas that would require additional prims, which are not obvious. But, they do give the pedestal a better look.
A problem with the prim build is in the texturing. I would also need 6 or so textures. A detailed texture for a sculpty is a real PITA.
With the mesh pedestal (on green grass) in the image I chose to use two meshes. One is the more cylindrical base and the other the more square-ish top. I mixed UV projections by using different projections for various parts of the top when making the top’s texture.
The base currently shows a prim equivalency of 2.4 to 3 prims and the top 2.0 to 2.4 prims. Say 5 or 6 prims total, which is about half the pure prim build. A real savings comes in the textures. I only use 2 texture images, one each with the meshes. The top is 1024px sq and the bottom 512px sq. If I had not been experimenting, I might have made the whole pedestal from one mesh and only needed one texture and 512px would be more than adequate.
The mesh version renders much faster than the prim versions. In regard to download speed I find it hard to tell whether it will be better or worse. Downloading a prim is fast, very little data has to be transferred. The High rez versions of the meshes I made are in 61k and 209k Collada files. Plus there are the other LoD levels. The total size for the meshes are 133k and 397k.
A sculpty map file is about 12k. A texture 128×128 is about 49k. So, mesh files are bigger and will take more time to download. But, they render faster than sculpties. I suspect the time needed to decode the sculpty map may be part of the reason.
For clothes I use lots of transparency. I like PNG files and have my Photoshop making all my 24 bit PNG’s with transparency. That did not work so well with my meshes. These textures obviously do not need transparency and I should have turned it off.
In the image you can see a part of the pedestal top goes transparent when it should not. The red arrows point to the problem area.
I did not use transparency to get the hole in the pedestal. I built a hole. This build is/was an experiment. I might put this in a JIRA. However, the fix for me is trivial. Turn off transparency in Photoshop and make a new texture. That fixes the problem.
The problem is not limited to just the complex problem of rendering a hole in the model correctly. In the image showing the bottom of the base you can see the problem crop up again. We have seen transparency problems in lots of places in SL. Meshes are not immune to those problems. However, this second problem was also resolved by removing the transparency from the texture, same as above.
There are places where transparency is needed and it can be a problem. See the cars. There are lots of more serious problems ahead of fixing transparency. So, it may be some time before we see this fix.
Some of the Fun Stuff
Testing things on the ADITI grid puts one shoulder to shoulder with some interesting stuff, some really nice looking. Here are some pictures.