Tutorials

Inclusion / Exclusion

Object Exclusion + Inclusion rollup

Ignore Same Object

When this feature is switched ´on´, rays that hit the current object are ignored. Use it to solely take other objects into account. The scene below has a cylinder running through the cube.

Use Same Object Only

This option is very useful to ignore undesired objects. For example a scene imported from AutoCAD® contains both the facade of a building as well as all the interior (floors, cables, pipes, lift, stairs). For a nice facade rendering the interior objects can be ignored. This works especially well, when the facade object is a big mesh.

Neutral Scene	Ignore Same Object=On	Use Same Object Only=On

Ignore Object ID

This option is very useful for ignoring undesired objects. It is very similar to Use Same Object Only, however, a single object to exclude can be determined. Object IDs used here can be found in the 3ds Max Object Properties dialog (right mouse on object), in the General Tab - Rendering Control - G-Buffer. How to switch it off ? Use an Object ID of 0. The sample scene below uses a second cylinder. The cylinder´s object id is 3615. Note: Object IDs are ignored in the V-Ray version of RichDirt for technical reasons. V-Ray support of Object ids may change in future versions.

Ignore Object ID = 0 (off)	Ignore Object ID = 3615

Surface Offset

This is a trouble-shooting option, both for self intersection/surface acne and curved surfaces. The surface offset can be increased in such cases. Units are always in millimeters (1 inch = 25.4 mm). The default value is 3 mm. Surface offset lifts the start point of the cone, so rays start from a higher position and thus reduce self intersection. It is a bit similar to the bias parameter of classical shadowmaps. Surface offset can also be used for a few interesting effects like a worn out edge.
The scene below uses a twisted cuboid, to trigger self intersections. Although RichDirt is not guaranteed to work on curved objects, it works very well in the following example: in order to obtain the self intersections a strong twist + Follow Up Slope + a smaller spread have been applied. A Surface Offset of 0.1 mm shows the effect. With 3 mm it is barely noticable, but a small effect remains. With 10 mm there is a visible gap on the cylinders - and the twisted cuboid looks perfect.

0 mm	3 mm	10 mm