Question about the Lux render engine

halfmast88

When using it how do I know for sure when its done rendering completely? I have Lux and the plugin for Daz. When I click render a dialog box pops up and text keeps scrolling continuously and sometimes when I eventually hit stop render the saved file is completely black (Not too dark just a black background so i think i quit too early but I don't know when to stop.

Herald of Fire

It never stops. Literally never.

It's constantly calculating more and more light rays with each pass, adding more samples as it goes. How long it takes is basically as long as it takes before you consider it 'good enough'. The speed will depend on your lighting setup, the scene and your material choices. Too much light bouncing around can slow renders to a crawl, and too little can make it very hard for the camera to find the light, giving you poor samples.

To give you an example, the image below was rendered using 1500 samples using a single mesh light.

SpottedKitty

FWIW, the measure of image quality for LuxRender (both Luxus and Reality) is the Samples/pixel value. You should let the render run until S/p is at least several hundred, more likely into the thousands. How long this takes depends a lot on exactly what's in your scene, what the materials settings are, and what your lighting rig is like. A render looking good after running for only a few hours is unusual; more likely you'll have to let it run overnight, or even for a day or so.

Note that the LuxRender GUI needs to be switched on, it's off by default. It gives you a lot more control over lighting (which can be tweaked on-the-fly as a render is running), among other neat functions. It's one of the settings in the Render Options dialog after you select the LuxRender renderer.