Sclupted prim issues

There are several issues with sculpted prims.

1. You must keep pixels next to each other different in color to prevent the LOD system from turning it back into a sphere when you zoom in.
To see this create a .5m prim with the sample box texture in the library and zoom in.
It changes back into a sphere when it's large.

2. It rejects small images.
Why can't I create a 2x2 image and use it to create a flat plate.

3. It forces you to close the shape.
Why can't I create a one sided shape?


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I see a lot of potential, but here are some things I would like to see.

1. An "invalid" color where if any of the 3 pixels of a specfic tris has an "invalid" pixel that entire tris would be left out. I see this being used to reduce a lot of the Alpha sorting issues.

2. Don't close the edges.
Make the creator to close the shape.

3. Don't compress images smaller than 8x8 or have a Checkbox.

4. Allow 2x2 images to be uploaded.
I get a "no error" error message.

5. Don't change the LOD if the texture is smaller than 16x16

to solve part of your problem.
/8/75/180494/3.html#post1498712/8/75/180494/3.html#post1498712
This will make a flat plate you can draw on like a height map.
remember the base shape is a sphere there will be problems at the edges.

This is only the first version of the sculpt prim. don't expect this poor little prim to do every thing. But it pretty amazing how you can do with it. The look and feel of SL will change forever.

I agree that they are useful.

I also realize that the limitations are due to other factors.

1. It has to close the shape since Image compression and LOD changes would make it almost impossible to manually close a shape. The shape is closed by wrapping from the top of the texture to the bottom and from the left to the right.

2. An "invalid" color would only work if you could disable image compression and lock the LOD level.

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Possible future improvements that would be compatible to existing definition.
1. Lossless image upload option for textures smaller than 32x32.

2. Alpha channel in the shape texture to create holes.
This would let you make a 1 prim grass shape like the linden grass.

3. Disable LOD for smaller textures. I got 8x8 to work.

4. Add the ability to lock the LOD level on all circular prims.
This would let you turn a cylinder into a stop sign, ect...

Iteresting idea. if we uploud a smaller LOD make it so it can't got above that LOD. hmm. Cut way down on the polys we see then.

Actually, I am wondering a few things...

I would imagine that they are using a vertex shader program to make these, and that the normal map takes up video memory just like any texture. Question is, how many of these "images" can be expected to be stored on an average card, along with all the other data for describing the scene?

Are we really going to see widespread adoption of these such that there may be hundreds to thousands of different sculpted prims in any one scene? What's the performance impact of these for various generations of video cards?

Inquiring minds want to know...

As far as I am able to tell this is done in the client.

The texture and Prim object are used to create 100's of tris (3 point triangles) which are then sent to Open-GL to be rendered.

Another possibility is that the texture and the prim are used to create a 3D mesh that is sent to Open-GL.

Either way the shape texture is not sent to the graphics card since it must be first resized and rotated based on the Prim.

And it should have better performance than using lots of twisted and tapered tori.

Just out of curiousity, is there any info on this in the talk section of the wiki Torley put up on sculpted prims? I know that Qarl Lnden has been posting there and answering a lot of questions/comments on scupted prims.
http://wiki.secondlife.com/wiki/Talk:Sculpted_Prims

Yes but what a pain to follow those. The formatting is horrible to follow. Reminds me of "vertex vomit".