partially hidden object

Hello Blender-Artists,

as I’m realy new to blender I need some help.
I want to define an boundary for an object, so at the left from this it should be visible and at the right it should be hidden. The background and all other objects should not be affected from this. So while animation the object should disappear when passing this border. Any ideas?

sry for my bad english

There is a material option in Blender Internal just for such a task. Basically you use one object to ‘mask’ another object. So the masking object needs a material set to ‘Mask’. The render shader must be set to transparent to actually get your alpha channel, otherwise the sky shader will occupy the mask space.

The mask is only a visible technique. And by that I mean you are not really affecting geometry thus shadows produced by the object being masked are not masked.

For simple reveals in controlled cases you could leverage the mask technique but if you really need your shadow to work correctly you may want to think in terms of an animated boolean reveal.


26_mask_via_object.blend (92 KB)


the first thing that comes to mind is a boolean modifier. Use whatever primitive as a substractive object (a cube, say). Or… I think the holdout shader in Cycles is aimed at hiding things, too, but haven’t used it before, you might want to check that.


Thank you very much. I going to try out this.

Thank you very much.

I added a new cube and turned of visibility. Then I added the difference boolean modifier to my object. Now it’s exactly what I want. Seems so simple now :).