“FastRad” is a collection of settings for configuring radiosity in the free raytracer POV-Ray. To see tutorials on how to get started with LDraw (LEGO CAD tools), head over to LDraw.org. This tutorial assumes you already have LDraw and POV-Ray installed.FastRad will give you results something like the image below:
First, download the following files:
- Fastrad.inc needs to go into a folder that POV-Ray is searching. The best location for this is in POV-Ray’s own include folder. You can find this is under the POV-Ray directory on your computer.
- Now, launch POV-Ray and open up any freshly-converted L3P file. For this tutorial, I'll use pyramid.dat. Below is what the raw file looks like.
- Scroll down to the bottom of the file, to the light statements. For the best and quickest results, pick one light source to keep, and delete or comment out the other two.
- Scroll up a bit to the floor statement. To get a plain white floor, change the pigment and finish to match the statement below.
- Next, go to the top of the file, and find the line "#declare DIF = 0.4;". Under it, insert the code "#include "fastrad.inc" to load FastRad's default settings.
You’re done! That’s it! Those are the steps for using FastRad with one light source, which is what it was designed for. For more in-depth usage, and some tips and tricks, keep reading on. Keep in mind these aren’t in any particular order. - Rendering without light sources: To light the model with only the sky, you need to change some of FastRad’s parameters. Remove the light sources from the model file, then insert the following lines at the top of the file. You may find you need to switch to the high quality setting, as setting 1 will show some artifacts.
- Using a blue sky: Insert the following line above #include "fastrad.inc" to get blueish shadows.
- Simulated radiosity: this uses no radiosity at all, but approximates the shadows with basic ambient light. Because of this, you need to use a light_source in the model file. The floor pigment and finished needs to be tweaked a little, too.
- Area lights: a great way to add more realism to the model. The size of the area light is specified in the x,y,z coordinates (<35,0,0><0,0,35>). The number of lights within the area light is set immediately after (5,5—choose bigger numbers for smoother shadows). 'Circular' positions the lights in a circle, 'orient' aims the area light at the model, and 'jitter' further increases the smoothness of the shadows.
- Floor spot: used with setting 3 (simulated radiosity), this creates a convincing dark patch under the model. Depending on the model’s size, you may have to increase the 'scale' value. Also, if your model isn’t centred on the origin, use the centre value (from the statistics at the bottom of L3P-converted files) as the new 'translate' coordinates.
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