Deborah R. Fowler
Houdini Lighting
Posted Jan 28 2018
Instanced Lights with Geometry
TIP: This is a continuation of the section on Instanced lights - read that first here.
Now you have your instanced lights working, you want to combine them with geometry ...
There are several approaches to take here. Let's discuss them briefly:
- Change your instanced light to a geometry light and render the light geometry. What is wrong with this method is that you will not have individual control over the intensity/size of the light and the object. They will be tied together (as well as being more expensive to render)
- Change your point light to a sphere light and render the light geometry. This has the same problem as the above. It is less expensive, but still problematic
- Create geometry on the same points. This method is the best choice because you have control of the shader on the geometry separate from your light controls
- lights require FULL, geometry only requires FAST (instancing type)
- use ACTIVE RADIUS and link it to the ramp end value (see hip file - artist friendly fall off)
- do not block your lights with your geometry (see image below)
- check off enable on your light
- turn off the display on your intanced geo object (or use packed copy instead)
TIP: One of the most common errors is to cover your point lights up with geometry, remember to take it out of the shadowmap (or assign a seethru shader)
TIP: Note that if you have diffuse limit with PBR on there will be bounce light/color bleed as well as seen in the image above. Below is a version with diffuse limit set to 0.
TIP: Excellent documentation exists on removing noise in mantra from SideFX