Render booleans
Inside Hubble's eye. Using objects to clip the model and see the interior of the telescope.
A Render Boolean is an object used to cut other objects in the scene, usually to show their interior. The cutting is performed at render time and the cutting object can be animated, providing more flexibility than cutting in the modeling stage. This is useful for architectural or industrial design projects to show the interior of a building or a prototype.
The cutting shape can be a box, an sphere or a plane - this is fully customizable. The cutting works in a similar way to the camera's Z-clip feature, except that it is no longer limited to just the camera's near/far planes. The main advantage, compared to using z-clip, is that you can freely move the camera without affecting what gets clipped; you can create different sizes and shapes to act as clipping shapes; and that you can freely animate the cutting object.
To convert an object into a cutting Render Boolean, simply select it and in its Objects Attributes panel, and choose the desired cutting shape among the Boolean dropbox options.
None: Disables the cutting behavior.
Box: The object's bounding box will be used as the cutting shape for the rest of the objects in the scene.
Sphere: The object's bounding sphere will be used as the cutting shape for the rest of the objects in the scene.
Plane XY, YZ, ZX: The object's local XY, YZ or ZX plane will be used as the cutting plane. Everything in the negative direction of the chosen local axis XY, YZ or ZX will be hidden to the camera. You can rotate the object to decide which way the negative axis is pointing. Easiest to use if the geometry is already a plane.
Setting an object's bounding box to be used as a render boolean to crop other objects in the scene
IMPORTANT
Keep in mind that the cutting, just like the Z-clipping, will preserve the original lighting of the scene, so if you want to see the inside of a closed object make sure you add some emitters inside it.
Render booleans in action
In order to unify the look of this documentation, the screenshots in this chapter were taken from the Studio interface, so they may look slightly different in other 3D platforms.