pixelated displacement in Renderman for Maya

[ACamacho]

Just for curiosity, can you post the texture map? Also when you say "changed the filter", I assume you meant the render globals filter? On the filemap node itself, there are some "texture filter" renderman attributes you can add. Try setting it to radial b-spline (think thats the name). This is optional but may work out better you you.

It's also hard to see the aliasing in the examples you posted because of jpeg compression.

[jasonhuang1115]

Thanks AGAIN, ACamacho!

Yeah, I tried several global filters and play with the Maya default file texture filter type and size. Here is the updated render.

http://farm3.static.flickr.com/2207/2192348645_173d8bbd02_o.jpg

I tried the radial-bspline filter and crank up the S/T width to about 3. It helped a bit, but still is not what I want.

http://farm3.static.flickr.com/2300/2192348677_5fd50116c2_o.jpg

If I keep cranking up the S/T width or blur the 1 pixle line in Photoshop, I will not get thin and sharp enough indentation that i want to achieve.

I have attached the scene and texture file. The texture path might need to be redirected.

[ACamacho]

Hmm, well according to the texture the renders you are getting are accurate. Your lines have no antialiasing in the texture. When I created slightly thicker lines (using the line tool), things got a little better.

http://www.angelcamacho-torres.com/files/cgtalk/test_rman_lines.jpg

[jasonhuang1115]

Thank you, Angel for the quick and detailed reply. :)

So, the problem is actually from the texture? Theoretically, if I want to get thiner indentation, I have to double or triple the resolution of the displacement texture map and in that, use a thicker, softer pen/line tool to get rid of the aliasing edge along the lines, correct?

I found when I zoomed out on the geo, the indentations got blurred(not well defined on the edge). It can be fixed by creating a custome shading rate for that geo and lowering it to 0.1. Is there other way to keep the displacement sharp while zooming out without lowering the shading rate to that low? (I can't go lower than 0.1)

Thanks!

[ACamacho]

Thank you, Angel for the quick and detailed reply. :)

So, the problem is actually from the texture? Theoretically, if I want to get thiner indentation, I have to double or triple the resolution of the displacement texture map and in that, use a thicker, softer pen/line tool to get rid of the aliasing edge along the lines, correct?

I found when I zoomed out on the geo, the indentations got blurred(not well defined on the edge). It can be fixed by creating a custome shading rate for that geo and lowering it to 0.1. Is there other way to keep the displacement sharp while zooming out without lowering the shading rate to that low? (I can't go lower than 0.1)

Thanks!


On your first question, yeah I would think it needs to be thicker to get nice AA on the edges. Your right in that you might want to try a 4K map and see if that helps. If you have to go 8K or higher, try modeling it. :)

Yeah they were blurred because of the filter size. Putting it back to one fixed that, but then the pixelation came back. If you have to put the shading rate at 0.1 to get good results, again try modeling it.

[jasonhuang1115]

Thank you, Angel. Sorry for the late response. I've been having FUN with creating brickmap for my scene. Got lots of questions and will post it probably in next couple days after some more testings. I read some documents from escape studio's renderman courseware about point cloud and brickmap baking. It seems a really cool feature but with some limitation while tons of geos stacking with each other and colorbleeding. My project happens to have lots of geos close to each other and I always have some blotch spots in the renders while using baked brickmap. Anyway, I will do some more test-renders and post it. :)

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.