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omichon
02-24-2007, 01:43 AM
I have a scene with a reflecting object laying on a large white ground, that produce no exciting raytraced reflections.
So I have put some env map on it but I have to define the reflection to sperical map only to see it.
The problem is that I need to get some of the raytracing reflections at the contact point with the ground and in the inner corners of the object.
So the question is :
Is there a way to add some raytracing reflections over a spherical map reflection layer limited by an occlusion mask ?
Thanks for any node suggestion.

omichon
02-24-2007, 02:51 AM
Well, I put two Reflections shaders into a Mixer, with opacity defined by an Ambient_Occlusion (thanks for it, Denis :) ) and it seems to do the job, basically.

Dave Jerrard
02-26-2007, 02:18 AM
Have you tried using Ray Tracing and Spherical Map in the reflections mode? This will ray trace everything except the backdrop, which will be replaced by the spherical image you give it.


He Who Used This A Lot For Doing Metals.

omichon
02-26-2007, 02:44 AM
Thanks for the suggestion Dave.
The problem in this case, is that the ground polygon is so huge that when looking from above, the env map is never seen in the reflections (except on the top of the object). The idea would be to have the ground unseen by rays, but in this case I miss the contact reflections between the object and the ground.
I tried to figure out a workaround by rendering different layers, but it's not that easy to comp.
I also tried to set the ground unseen by rays with an additionnal smaller ground unseen by camera but it's not yet satisfying.
I don't know if it is possible to define a max distance for the rays used in the reflections with the node editor, but it's my last hope :o

dpont
02-26-2007, 04:55 AM
The Raytrace node is not limited internally, but you
can input the Ray Length in A in a Logic node, the max distance
in B select "Lower..." and output the result (true = 1) in a Mixer opacity,
to exclude such far reflections.

Denis.

omichon
02-26-2007, 05:35 AM
The Raytrace node is not limited internally, but you
can input the Ray Length in A in a Logic node, the max distance
in B select "Lower..." and output the result (true = 1) in a Mixer opacity,
to exclude such far reflections.

Denis.

Well, the raytrace node is not limited, but my knowledge about nodes is very limited :stumped:
Anyway, I see the idea. I will play with it.
Thanks, Denis, for the suggestion :)

BTW, do you think it would be possible to add some fall off on the result, because I am afraid that a ON/OFF flag on opacity could produce some wacky results.

dpont
02-26-2007, 06:28 AM
You can do a falloff effect with a Gradient Node set the
Length in the Gradient input, in the Gradient panel set a
value of 1.0 (white) for an input (Length) of 0.0 and a
value of 0.0 (black) for an input of max length.

Denis.

omichon
02-26-2007, 07:53 AM
Thanks again Denis, I will test it.