Is there a way to have houdini generate and use planar reflection maps automaticaly? I know how to do environment maps, but I cant figure out how to create and use planar maps.

Please help


RudyC

Hopefully I'm not being thick - but by planar reflection map do you mean cubic reflection map? If so, look at the object you want the relfection on, Shading tab, and toggle on “Auto-Gen Reflection Map”, and set a location, name and size for the map. When it's done, mplay it - you'll find it contains 6 layers representing the six directions - you can use it directly as a CRM - no need to massage separate images.

Cheers,

J.C.

Hopefully I'm not being thick icon_razz.gif - but by planar reflection map do you mean cubic reflection map? If so, look at the object you want the relfection on, Shading tab, and toggle on “Auto-Gen Reflection Map”, and set a location, name and size for the map. When it's done, mplay it - you'll find it contains 6 layers representing the six directions - you can use it directly as a CRM - no need to massage separate images.

Yeah, I saw those, bot that generates an EnvCube map. and it usually doesnt index properly for a flat surface. Im looking to generate a regular ol' reflection map. Which are usually the whole scene inverted, using the center of the flat surface as the pivot. That image is then indexed using NDC coords.


Thanks a lot for your help thoug

Cheers
Rudy

rcortes
Im looking to generate a regular ol' reflection map. Which are usually the whole scene inverted, using the center of the flat surface as the pivot. That image is then indexed using NDC coords.

Hi Rudy,

Well; I wouldn't call what you're trying to do a “regular ol' reflection map”. There's nothing “automatic” or “regular” in what you describe (which is PRMan's application note #6).

First you need to generate the reflected image (the one that gets index through NDC), and to do this you have to reflect the camera about the reflecting plane, then render from that camera (removing all occluding objects) as a normal image (not a lat-long or cube map). Finally, in the shader for your reflective surface, you look up that image (again; it's not a reflection map) using the main render camera's NDC space (and bound by the extents of the reflective plane – the mirror, or whatever).

In other words; do exactly what the Renderman application note says to do.

(Oh; and of course, you could always ray trace it instead, and save yourself all the headache 8) )


Cheers!