Issue with back face culling 3D Max Design 2012

[Kerry Thompson]

We have a work flow where we take Revit generated materials, write them out to .fbx files, link the .fbx files to max and then generate a material library of Autodesk generic materials. The building we are rendering has a brick cladding and we are trying to render out the brick with the mortar joints transparent. This will allow use to overlay the rendered image on different mortar colors.

 

The building model has been built in Revit 2012, written out to an .fbx file and then file linked into Max Design.

 

We can render the brick with the mortar joints transparent using the cut map but the blackface culling is not working - we are still seeing the inside part of the wall through the transparent mortar joints. As I understand it, blackface culling should drop out the inner faces of the wall but I have not got it to work to date. We are using a lens camera effect to isolate the objects that use the material within the render.

 

The normal modifier has been added to rthe walls and unified.

 

Any one have any ideas why the blackface culling is not working.

 

Thanks

 

 

Kerry Thompson at Triptech

[id_ivan]

Hi,

Could you post your screenshot? What render engine do you use? What lens camera effect do you use? Perhaps you checked Force 2-Sided in render scene dialog?

 

Anyway, this is default behaviour in vray no matter how you set it up, backface wil allways got rendered.

[Corey Beaulieu]

Why not just render a matte for the grout and alter it in Photoshop? Select the faces you want and detach them from any other faces. In Object Properties (right click is the fastest way to find them) set a G-Buffer number. Add a MultiMatte in the elements and make sure the g-buffer number matches on of the channels in the element. With this you can colorize, hue change, even material map change if you are savvy enough in Photoshop.

[Kerry Thompson]

Thank you for the replies:

 

The render engine is the Mental Ray shipped with Max 2012 and the Camera effect used is the Lens which is set-up to render out the objects for one material only. We have got a workaround using ImageMagick scripts which are able to cut out the mortar joints to give use the effect required but I understood that Max would Backface cull directly. We are using Autodesk generic materials generated from Revit 2012.

 

[ATTACH=CONFIG]46789[/ATTACH]

 

The blue in the image is the added background and shows through at the edge of the render until we see the backfaces of the wall returns.

 

Kerry

[datacrasher]

Display display propties check (tick) the box

 

 

 

Backface Cull on Object Creation—Determines whether to display faces with normal pointing away from view. When turned on, you see through the wireframe to the backfaces. This option applies to wireframe viewport displays only. In most cases, you'll want this item turned on. However, if you're modeling with NURBS surfaces, which consist of single-sided planes, it's easier to view them from all angles when backface culling is turned off.

 

• This control affects only the created objects, and you can reverse the effect on each object by changing the Backface Cull setting in the Object Properties dialog for that object.You might turn off Backface Cull On Object Creation before creating your NURBS, and then turn it on again when your finished.
  
• You can globally change the display of backface culling in the viewports by turning on forced 2 sided on the Rendering Method panel of the Viewport Configuration dialog.
  

[Kerry Thompson]

Thanks datacrasher.

 

I have set the backface culling as you suggested and but it does not address the issue.

 

I have run the Autodesk Generic materials in a very simple model and the back face culling still does not work. I rebuilt the material as a Arch and Design Mental Ray material and set the backface culling on in the Advanced Rendering Properties. This material backfaced culled on the simple model but not on the complex one.

 

 

 

 

Kerry Thompson at Triptech

[datacrasher]

kerry

I don't know what to tell you from you're image it looks like there are gaps in the wall i would add a shell modifer not this is not fix the gaps in the wall. what i would do is complete make the wall in max by making a box then adding the material to your box then add a VUW map and set the tiling in the U and V 4.0 by 4.0 IMO

 

if that ImageMagick scripts works why not use it?

 

if you create a plane in the front view then roate it you notice there is no back then tick (check) the backfacing culll then that will show the back of the plane

 

Tony

Edited January 18, 2012 by datacrasher
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