[Thomas An.]

Hi everyone,

Since, there is not much information about the Camera Cosine option, here is a little schematic I put together explaining what I think is camera cosine and how it behaves.

If you have any more in depth information about this topic (or if there is any error in this explanation) please post your comments.

[rivoli]

um, i don't really have a clue about how to make this channel of any use. some kind of custom made fresnel reflection?

100% diffuse pass:



100% specular pass:



coscamera mask:



odd fresnel reflections?

[Thomas An.]

Rivoli,

Very interesting screens. Thanks for those.

I have been thinking about the uses of coscamera too, but like you, I am not 100% sure of what to do with it.

Now, did you try to use plastic material and put the coscamera as specular map on that plastic ?

[rivoli]

Now, did you try to use plastic material and put the coscamera as specular map on that plastic ?

no, i never thought about it. but i don't think you could map an object with a map like that (maybe if the object was perfectly orthogonal to the camera, and you still would have problems due to prospectical aberrations when unwrapping and appling the planar map).
as sinik says, the mask can be useful for compositing and blending effects, only thing rendering different passes for with maxwell (same object with different materials or textures to blend together in post) is reeeally expensive in terms of render time.

[Mihai]

Like sinik mentioned, what you would use it for in other packages is controlling effects like reflection and fresnel. Could be useful for procedural textures as well, for example think of sparkling snow.

Nice tests again Thomas, are you a teacher?

[Thomas An.]

Sinik, Mihai,

Any links you can share ?
(Showing stepwise images of how this channel is used in post ? )

[Mihai]

Well for example to achieve a fresnel effect on the reflection in XSI you would connect an "Incidence" node into the reflection strength node of a material.

Now this incidence node has several options on how to compute the angle, either based on camera to surface (like Maxwells cosine camera), or lights to surface, or a certain light to surface, or an axis etc......

So it just gives you a greyscale map which for example can be used as a mask for other effects. Example you can make a dust procedural, plug the incidence node into the procedurals strength node, set the incidence angle to Y axis, and this way the dust procedural will only be visible in the top of the object.

[rivoli]

well, mihai, also in max you have something like that: a falloff map with different falloff types and directions/axis. but this has very little to do with the coscamera channel, which is a mask that can be used only in post.

[Thomas An.]

Non of my tests yielded anything usefull. The fresnel thing is just as what Rivoli mentioned. I tried other blending modes trying to make custom metallic shaders and its not too promising, besides we are going to get realistic materials in the final release anyway.

I think its a useless channel.


Highly specular plastic


Plastic blended with CameraCos ("derken" blending mode)

[rivoli]

besides we are going to get realistic materials in the final release anyway.

yes, maxwell will surely have its own blending maps (normals dependant, like falloffs or incidence masks/maps, and density dependant), with the mat editor.