[Maya] Render all ABOVE Groundplane

Alphavader

Hi there,

i currently working on my stonepit,
(here a WIP Pic)

and have some render issues - maybe you can help me !

Here a screeshot that may explain my problem:
(I want to seperate groundplane and object - works well with renderlayers,
BUT - when i seperate it - Maya renders all UNDEr the groundplane.

Is there a function that says, "render all what you see" and seperate groundplane from rest ?

Hope you can understand my question

Thanks guys !

Sharvo

Hey i think i understand what you mean, i havent used maya in awhile. But, under the attributes for your ground plane you can turn off some render boxes, like primary visibility, so it wont render but will cast shadows etc. Another one is recieve shadows, so it wont recieve it. These are under 'render stats'.

Something i used at Rare is a background shader, its pretty simple to use just go to assign new shader and choose the background shader. You then have some values you can change in that.

If you are using render layers, one i always use is an idRenderLayer, i use different flat colours for different objects or materials for example in your case groundplane have a flat blue colour and the rest have a flat red, so when i am in photoshop i can select between the two very easily.

Hope that helps!

Edit: i think you will be best with my selection shader idea and the background shader just realised you wanted the stuff under the groundplane not to show up!

Alphavader

Thanks Sharvo for your reply,
ill allready have a backgroudshader, called
mip_matteshadow with mib_transparency for backgroundcolor !
Workes well for Alpha channel and seperating, but didnt work when somethink
is under the plane

Isnt there a function, that says " render all as if it (groundplane) were there, but seperate groundplane and rest ?!

rube

if you apply a 'surface shader' material to your ground it will cut it out of the render. Just drag the 'Out matte opacity' to black in the shader.

Alphavader

no that doesnt work eithe.. sorry

Mark Dygert

Yea, in max this is easy, just use a MatteShadow material on the ground plane. I'm surprised that doesn't work in Maya, it gets used in film all the time.

Alphavader

i used the mip_matteshadow for my groundplane,
that worked well for alpha channel and rendering the shadows only,
but doesnt work that way i want it to be ;(

Sharvo

Hmmm, that is very weird surface shaders should work fine.

If thats not working try creating a new lambert and set the ambience to the same colour as your diffuse. For example red. Assign this to your groundplane.
Then get the other objects and create another lambert set that to blue do the same with the ambience. When you render you should have two seperate flat colours the red and the blue. Then you can select the bits that need deleating.

Not sure why the surface shader or the background aint working though, they do on mine, lol!

Mark Dygert

If the alpha is fine, use it as a mask.

rube

I'm not really sure why the Surface Shader isn't working for you.. I use that feature almost daily and it does exactly what I understand you to be looking for. Do you have a render of what you get when you try that?

Alphavader

Thanks for your reply guys.. so no, it doesnt work that way..
here a screeshot that explains better.
Maybe its a issue between the renderlayer settings and my shadernetwork..
Ahh and the Groundplane Layer is only black, no Alpha

Alphavader

Update:
i rebuild the entire shader, the use_background shader does
it !! - with shadow and alpha !
THanks guys !

Alphavader

there is one problem left,
my ambient occlusion has no alpha map !
it batchrendered the groundplane ! as you can see
down below.. meoow

Alphavader

Here a Picture

Alphavader

Any suggestions how i can combine the "use_backgroundshader" with AO batchrender
and get an alpha channel ?