So, I'm attempting to create random lit windows for buildings in a scene, and someone suggested using a particle system and use the textures as emission planes. So far I can create the lights, but getting them where I want them, and making them the size of the faces is another story. Here's what is happening:

enter image description here

Above I tried setting up a mesh that consisted of faces for each window (green), and a vertex group to go with it (weight 1.0). I couldn't get the particles to stay in the faces as shown. I also moved the particle system to the building, and used a copy of the specular map texture to control it, while using the influence of size/length (1.0) for the particles. Still, the result was like the above.

It feels like I'm missing something small, but not obvious. I'm wanting the emission to come from the separate faces, or from the black portions of the texture, as well as each being the size of each. Can anyone shed some light on this issue?

Thanks in advance!

  • 3
    $\begingroup$ Could you provide a .blend, or at least give an image of your particle settings? Currently it's really hard to tell what your having trouble with, especially since the screenshot you provided doesn't really show anything. $\endgroup$ – TARDIS Maker Jun 5 '15 at 17:45
  • $\begingroup$ I cannot. Some models are not to be disclosed, as well as their textures. Sorry. :( Any information to help me understand the system's placement, and using textures to control it would be a huge help. Still-life and the emitter system doesn't seeing to be a popular topic from what I've found on my own. $\endgroup$ – DBrown Jun 5 '15 at 19:41
  • Animation below.

enter image description here

  • In the image below note the settings Particles/Face set to 1. Face Jittered Random. These setting respect the faces created in the geometry. This the preferred setting for more varied geometry. The image has an extra windows on the right side to show how these settings respect faces. Plane subdivision is a requirement.

enter image description here

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  • $\begingroup$ Ah, that would make a lot of sense. As you may have noticed, I'm using a square plane, so instead I will create copies of the faces as these emission planes, and randomize. $\endgroup$ – DBrown Jun 5 '15 at 19:34
  • $\begingroup$ I'm really not sure why I thought I could fit different sized emitters to faces that were different shapes, but I did. Even this building in the screenshot is the same size as each part of the grid for the hair particle system it's a part of. $\endgroup$ – DBrown Jun 5 '15 at 19:38
  • $\begingroup$ You [may be able to] through scaling. I am suggesting you consider that as a premium event. More work. $\endgroup$ – atomicbezierslinger Jun 5 '15 at 19:59
  • $\begingroup$ Thank you again. Even though the windows are textured, I found a way around that. Now I have the light plane, or cube rather, inside the building model. The building texture has a slight tweak, where the glossy from the spec is mixed with a transparent, with the spec map driving the factor. Now the light can go through these virtual windows so the light gets out, and the gloss disallows to see through the building. I'm definitely going to play with particles a lot more now. This is great. :) $\endgroup$ – DBrown Jun 5 '15 at 23:00
  • $\begingroup$ Did you use particles per face ..................... or grid? $\endgroup$ – atomicbezierslinger Jun 5 '15 at 23:19

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