Downloads and Support

If you’ve tried to use Prim Composer to bake a texture across multiple prims, you might have noticed some seams when you import into SL or OpenSim.

seams on baked prims

At first, I thought this was a bug in Prim Composer, but now it looks more like it is a bug in the SL viewer.

You can verify it yourself with a simple experiment using only the SL viewer.

1. Upload a texture that is half red and half white (red_white.png).
2. Create two cubes and place them so that they are exactly side by side.
3. Apply the red_white texture and rotate the textures so that the white part is in the middle of the two prims.

red seam in middle

When I do this, I see a red seam going down the middle of what should be solid white. It looks as though the texture has been very slightly offset from where it should be. As a result, a very small part of the red side is wrapping around to the white side.

VWR-9013

I’m fairly certain that this is a bug in the Official SL Viewer and have reported it in JIRA as [VWR-9013]: “Texture Seam Bug: UV mapping of prims is slightly offset”.

Update – Texture Bleeding

After talking to a couple of people and doing some reading, looks like this is a case of texture bleeding which is a well known problem in 3d graphics and games. I tried in vain to find a good technical reference link on the web that would describe the causes of it. Instead, I found lots of people saying: “My texture’s not right.” And other people replying that you need to compensate by extending the texture a little bit outside the UV map. If anyone has a link to a detailed technical explanation about why it happens, I’d love to see it.

Anyway, I’ll be fixing this in the next release of Prim Composer which will probably be around Sept 19th. I’m on vacation next week.