Controls the rendering duration type to be used by the render engine.
| Type: | Integer | 
| Saved in: | Drawing | 
| Initial value: | 0 | 
| 
			  Value  | 
			  Description  | 
|---|---|
| 
			  0  | 
			  Render by levels; quality of the rendered image is based on the number of levels, or iterations, specified by the RENDERLEVEL system variable. Iterative rendering continues until the target render level is achieved.  | 
| 
			  1  | 
			  Render by time; quality of the rendered image is based on the number of minutes specified by the RENDERTIME system variable. Iterative rendering continues until the time has elapsed. Note: The number of levels, or iterations, that the renderer completes in the specified time is based on the complexity of the 3D model. 
			  
 
		   | 
| 
			  2  | 
			  Render until satisfactory; rendered image is refined iteratively until the rendering operation is cancelled.  |