Problem with my Photogrammetry shader in VRAY

[didier.muanza]

Hi guys ,
does anyone can help me on this:
I have built a view-dependent projective texture mapping shader ( multicamera projection shader based on incidence and occlusion for blending textures)
using maya. Actually my shader work with both Maya software and mental ray, but not with VRAY ( i ve recieve that message: ... Unsupported Kd TextureSpolight... )

I need badly to implement that shader for VRAY , but the method of occlusion and masking calculation I use ( based on Maya SpotlightFractionShadow) doesn't seem to be supposrted by VRAY...
Basically I 'd like to know if anybody can help me on this topic??

Cheers

[vlado]

V-Ray does not support the light data parameters, since it works in a completely different way internally. There are several options here:

First, the recent nightly builds allow you to add V-Ray parameters to the Projection texture nodes to make them take into account occlusion from the projection camera (which I guess is similar to what you are doing).

Second, we can code a separate texture that gives you the occlusion between any two points - then you can connect one point to a samplerInfo texture to be the current shaded point, and the other point can be the position of the projection camera.

The third option is code your shader in C++, which would be more complicated.

Best regards,
Vlado

[didier.muanza]

Hi Vlado ,
Thank for the solutions. Is it possible have a build where there are the V-Ray parameters to the Projection texture nodes to make them take into account occlusion from the projection camera and another option which would be like what you said: " a separate texture that gives you the occlusion between any two points"
Is this new code would allow me to:

1. Assign each original polygon an ID number. If a polygon is subdivided later, all
the smaller polygons generated share the same original ID number.
2. If there are intersecting polygons, subdivide them along the line of intersection.
3. Clip the polygons against all image boundaries and any user-specified clipping
regions so that all resulting polygons lie either totally inside or totally outside the
view frustum and clipping regions.
4. For each camera position, rendering the original polygons of the scene with Zbuffering
using the polygon ID numbers as their colors.
5. For each frontfacing polygon, uniformly sample points and project them onto
the image plane. Retrieve the polygon ID at each projected point from the color
buffer. If the retrieved ID is different from the current polygon ID, the potentially
occluding polygon is tested in object-space to determine whether it is an occluder
or coplanar.
6. Clip each polygon with each of its occluders in object-space.
7. Associate with each polygon a list of photographs to which it is totally visible.

[MatthewRF]

doesn't really answer your question, but i thought it might be helpful:

http://www.glyphfx.com/mptk.html

[didier.muanza]

does it work with VRAY?

[MatthewRF]

only if you bake the material.

[didier.muanza]

AH I see, So , it does the same thing as my tool... Actually My tool is working already with maya software and mental ray , but not with live interactive projections through , let 's say VRAY RT... I suppose I ll wait to test the new build that Vlado was talking about.

[vlado]

The projection occlusion options are now in the nightly builds; please email me to vlado@chaosgroup.com for information on how to get them.

Best regards,
Vlado

[didier.muanza]

Hey Vlado,
I have a question for you. I m using now the occlusion attribute to do camera projection, HOwever the mask generated by the occluded geometry is quite sharp. How can I have it smooth or driven by a ramp or a gradient?