| Directory | Description |
|---|---|
| IFD | Sample code for writing custom IFD render outputs. |
| FS | Sample code for writing custom files system extensions (FS). |
| GR | Sample code for writing custom display extensions. (GR). |
| CHOP | Sample code for writing custom channel operators (CHOP). |
| OBJ | Sample code for writing custom objects. |
| POP | Sample code for writing custom particle operators. |
| SOP | Sample code for writing custom surface operators (SOPs). |
| ROP | Sample code for writing custom output drivers (ROPs). |
| IMG | Mechanism for adding new image formats/devices to the image library for Houdini. |
| VRAY | Sample code for making extensions to mantra |
| expr | Sample code for writing custom expressions. |
| standalone | Sample code for writing a stand alone application. |