normal output of subdivided geometry

[br1]

Hi,

I'm having strange results when rendering subdivided geometry (with checking Polygon as Subdivision in the render tab of my node).

As soon as I activate Polygon as Subdivision, the output of my normal pass is looking really strange (it' s still there but nearly invisible, on some other models I' m getting holes or transparency issues). It comes back to normal if I untoggle it. I attached thwo pictures, one with the color, one with the normal output to quickly show what's going on.

I'm using a mantra surface as shader here, but had the same problem with, for example, a clay shader.

Any tips ?

Bruno

[ehsan parizi]

I had the same problem! I just subdivided in sop level instead of using that subdivision Polygon as Subdivision. I know it makes your scene way heavier, but I wasted 1 day and tried a lot of different methods, and none of them worked out. the funny thing is that if you render the same frame twice, the second time there's no weird artifact (at least it was like that in my project) but anyway, I hope someone has a better solution for it!

[tjeeds]

Hope I'm not stating the obvious here, but did you normalize N? If you don't the subdivision seems to return very low magnitude normals.

[br1]

Hope I'm not stating the obvious here, but did you normalize N? If you don't the subdivision seems to return very low magnitude normals.

What do you use to normalize N ?

I have the automatically compute normals toggled on. I also tried point sop and facet sop but it didn' t really change the resulting output.

Edited September 6, 2011 by br1

[majikal]

in shader.

I usualy create parameter with name NN (normalized normal), and then you set NN in mantra VEX variable field.

(remember to set export always in parameter node)

Edited September 6, 2011 by majikal

[br1]

in shader.

I usualy create parameter with name NN (normalized normal), and then you set NN in mantra VEX variable field.

(remember to set export always in parameter node)

Thanks for the info majikal.

Would it be possible for you to give me more information on where to place those node in an already existing shader like the mantrasurface ? I' m trying to modify that shader but am not really sure about where exactly I' m supposed to add these nodes. Is it within the surfaceModel ?

An example file would be great !

Bruno

[jim c]

I was trying this and this is still a "problem" (I don't know if this is actually a bug, or this is really the intended behavior) in H13. Would an alternate workaround be to create a simple custom material/shader, normalize the N global param and attach this to the shader output for N. Then you could just create a take and assign this shader to everything?

[_dv]

seems than is not a normals problem.

try to switch raytrace shadows off, and you lowpoly (no subdivided, left picture) geo must rendering ok

 

edited: oops, sorry, don't undrstand initial problem

with "polygons as subdivide" a very strange result in normal pass

 

http://gyazo.nivalnetwork.com/edit//d65728852e34e43b244d31a0f6d10c4d.png

Edited April 9, 2015 by _dv

[Skybar]

Hmm strange behavior, it seems to be a problem in the latest production build of H14 as well. However as stated above just do this in your shader and create an image plane from NN, it works fine then.