Sculpty/texture mappings changes with LOD

Has anyone else noticed that the mapping of a sculpty's texture to its faces changes as the LOD changes? I was experimenting with a geometrical texture on the beta grid when I discovered it. At first, I figured it was a new bug. But I tried it on the main grid, and it changes there, too. Interestingly, it doesn't change in the same way on the two grids. I'll attach my bitmaps if you want to see for yourself. As the LOD changes, you'll see the texturing completely change as the LOD changes.

My example here is probably close to a worst case, because the sculpty was modeled with an 8x8 mesh and then expanded to 128x128, and the texture makes the changes obvious.

At lower LOD the first pixels to be interpolated are the ones on the edge. As those are also the ones sampled for each LOD you'll end up with strange results. I think that by employing the technique where you center the sampled pixels (as we discussed before) you should have less issues.

I think this is a differernt issue, Blakar. (I did go ahead and try your suggestion. It mapped the texture differently, of course, but it didn't have any effect at all on the LOD jumps.) This seems to be an issue of the LOD adjustments in the sculpty bitmap and the texture bitmaps not being done in a commensurate way. Have you looked at my samples in SL? I think the problem will become clearer when you actually see it.

I was wandering around Luna, it didn't seem to be that much of an issue.

I think Sculpties are usuable only for certain types of prims, at least given the exporters we currently have available. I'm not yet confident it will cut down on prim count, though, but should allow for a more sophisticated level of detail.

I haven't been able to test in SL yet. I'll do so tonight. If it's a bug I'll write a patch. Unfortunately I haven't seen any 1.17.* source yet. As the mapping is different in Beta I need that source to make a meaningful patch.

There's already a Wings3D and a 3DSmax exporter allowing to export based on vertices instead of sampled faces. What's holding us back on making specific sculpted prims is JPEG2000 compression and LOD handling. But I'm sure both will be handled sooner or later.

What I figured out now, with mesh detail on medium or high a sculpt renders at 32*32 xyz points at the moment in second life.
Just wondering, when lod changes(so quick) it's changes to 16*16 / 8*8?!
(I got to check the texture test though)

Qarl? ...

I hate to be such a person "of little faith".

but actions speak. and so far, all we have seen is LL push sculpties onto the main grid before the "community" had a complete understanding and was ready. Hell, they even ran a sculptie contest, when a part of the community was still in tool-building-mode. building tools that LL will not build, but which are required to make sculpties pervasive and complete.

we've seen promises that things will be fixed. The same promises that I've heard over and over again in my tenure, but no schedule.

Why should I have faith now? The fact is I do, but I'm also ready to fall flat on my face. LL has done nothing to increase my faith in them.

I don't think Qarl is responsible for JPEG2000 compression. The good news is that in JIRA the related bug report has been raised in priority and is being handled by LL. I'm sure we'll see a change for the JPEG2000 compression.

I don't know who the author is of the current code that does the LOD handling of the sculpt textures but I am sure I can create a patch that does away with the interpolation. Once JPEG2000 compression is fixed it'll be useful to pursue this so I'll then make a JIRA entry and see if I can create an acceptable patch.

If the patch is small and simple and has proven benefit I'm sure they'll apply it.