Backface culling

[Stubb]

I have a model with some floating geometry and unfortunately the backfaces are showing up in reflections / are being rendered.
Is there a way to have all backfaces hidden?

Thanks.

[Stubb]

I have yet to find a solution for this issue.
If anyone can help it would be greatly appreciated.

[NM-92]

Can you post a screenshot of your scene ? This will help to understand what's the problem

[Stubb]

Yes, absolutely.
https://drive.google.com/file/d/0B1vHrErhR9IXSXhOaW1TXzIwclk/view?usp=sharing

As you can see, the back-faces of the floating holes are being rendered, which gives an undesirable result. I'm looking for a way to disable them or make them invisible to the renderer so they don't reflect or cast shadows.

[TpwUK]

If you are using KS6 and the scene is polygon based you should be able to flip the face normals in the geometry editor

Martin

[NM-92]

You can hide them from the scene tree if you unlink the materials. If unlinking doesn't work in keyshot you'll have to apply different colours to that set of surfaces in order to let keyshot recognize them as different pieces of geometry.

[Stubb]

I'm not quite sure how to implement the solutions you guys offered.
A more simplified version of the problem is this: I modeled a basic square plane consisting of only two triangles.
when importing it to keyshot, any material applied to the model acts as a double sided material, with both sides of the plane being rendered.
If I were to enable 'backface cull' in 3DSmax, for example, the side the normals face away from would be invisible. I'm looking for something similar within keyshot.

[TpwUK]

I'm not quite sure how to implement the solutions you guys offered.
A more simplified version of the problem is this: I modeled a basic square plane consisting of only two triangles.
when importing it to keyshot, any material applied to the model acts as a double sided material, with both sides of the plane being rendered.
If I were to enable 'backface cull' in 3DSmax, for example, the side the normals face away from would be invisible. I'm looking for something similar within keyshot.

There is the equivalent to this in the Geometry Editor that comes with version 6 or KeyShot. Which version do you have ?

Martin

[Stubb]

I'm on KS6, but haven't found what I'm looking for within the geometry editor.
Can you please explain where exactly I should be looking?

[TpwUK]

Open geometry editor window
Select part to edit (image-001)
Click edit geometry, you will get a warning notification, click continue
Select Edit Normals (image-002)
Click Show Face Normals, and adjust the size so you can see the blue lines and what direction they are facing
Set your minimum angle or leave as default if you are not sure, and then click Calculate Vertex Normals (image-003)

That should recalculate the face normals and flip them where needed.

Martin

[Stubb]

I'm afraid that didn't help, the normals didn't really need adjusting or fixing and both faces are still visible.
https://drive.google.com/file/d/0B1vHrErhR9IXU3JhNy1HZjBFekU/view?usp=sharing

[LayC42]

I actually don't know what backface culling is.
Maybe you can try this.
Place a plane with any material
Duplicate the plane and move it like an offset with a very small gap.
Change the material of the offset plane to emissive and toggle all visibility option
So there should be no reflections from the backside of the first plane.

[Esben Oxholm]

Hi Stubb.

LayC42's answer got me to think of a solution:

1. Make sure you have experimental features under 'advanced' in the preferences turned on (otherwise you will not be able to do step 5).
2. Create your base material.
3. Add an emissive material as label.
4. Uncheck all the visibility options.
5. Add the 'Surface Backside Mask' utility node into the opacity channel of the emissive label.

This should solve your problem. At least the plane gets invisible in the reflections in this example. See attached images.

Let me know if it works.

[Stubb]

That gives a very clean result. Thank you very much!

[LayC42]

Hi Stubb.

LayC42's answer got me to think of a solution:

1. Make sure you have experimental features under 'advanced' in the preferences turned on (otherwise you will not be able to do step 5).
2. Create your base material.
3. Add an emissive material as label.
4. Uncheck all the visibility options.
5. Add the 'Surface Backside Mask' utility node into the opacity channel of the emissive label.

This should solve your problem. At least the plane gets invisible in the reflections in this example. See attached images.

Let me know if it works.

Thank you Esben. Nice solution!

(I should start to write the answers here with a computer instead of my mobile phone.)