What is this Cmir ??!!

Hi to all

I have a problem with one of the (famous) parameter of blender texture : the Cmir parameter. It s a long time I m on this one and frankly I m disapointed ! I did want to post a message about it since it must be a long dating problem but after all my search I did not find any clues in the knowledge base nor on the forum. Finally after I saw the treatment of this parameter in the last (and former) blender manual i think it’s time to do something about this parameter : can finally somebody explain me CLEARLY (not like all blender doc) what is this parameter for, what it does, how I can see its full effects and so on. This is a real problem and it seems that all docs elude it as it was not clear for anyone !! So who masters the Cmir parameter ? thank you [!]

CMir stands for mirror colour (just like CSpec is specularity colour and Col is … colour)

Next to the RGB sliders are 3 colours, with a radio button under each one - they are the mesh colour, spec colour and mirror colour.

So if you apply a greenish texture as CMir and give the material ray reflections (I don’t think it applies to envmaps), then the reflection will have a green tint.

Thank you very much :slight_smile:

But to be really frank this doent help me much cause i have read all blender docs (last manual included) and sincerely there is nothing clear about Cmir. All you told me I already know it but the problem is that I m sure it’s much more complicated than this simple explanation… but how ? I think the best way would do to present visual information about the effects of Cmir. I waited for this in the last manual but there was nothing clear once again ! Nobody can explain the effect deeply. In the manual they just say “apply Cmir … and so on” but they dont explain why and what is the effect ! It’s not the only lack in the manual. For example there is not much explanation about the texture coordinates ! Why not explaining clearly and visually and exhaustively the effect of mapping X on Y or Z, disactivate X, or y or Z coord and so on. it really gives the impression that such matters was not mastered enough to be explained clearly which of course is not the case ! As said a French scientist, “what is well understand should be clearly said !” It’s simply not the case concerning many things in texure panel : Cmir, Sticky, X, Y, Z mapping and many other things but this are my favorites misundertoods. I only would like the team documentation be clearer and explains things much deeper than it’s the case for now :slight_smile:

Reading these articles a few times helped me:



The mirror colour concept isn’t that hard to understand - just try it and look at the result! Even the material preview gives a good idea!

But here’s a few renders to show exactly what it does:

Just a monkey above a plane:

Add some ray mirror (leaving the mirror colour on it’s default of white):

Change the mirror colour to green:

Add a texture set to CMir:

Then just to be weird, with the wood texture on CMir instead of Col:

Usually for metals and similar shiny objects the mirror colour is the same as the spec colour, maybe with less saturation.
Sometimes for more diffuse materials you have a mirror colour more like the material colour - put textures on CMir as well as Col
Mirrors of course have a Mir colour of white, to reflect all colours equally.

Philip: were you changing the parameters of the plane object or the monkey object? (just to be clear:)

The plane.
The monkey has no material at all in any of those renders.