particles and blur effects

    Sep 03 2013 | 6:53 am
    I’m trying to learn about particles and shaders. I think I have most of the basics down. The PartyLights recipe and a few other patches I’ve found in this forum have has been very helpful for me.
    I have a question though.
    How would you add an “un-blurred” object to the middle of PartyLights? I’m imagining blurred particles flying around a sphere that has not been blurred. Of course I can just naively add a gridshape object to the patch but then the sphere just hovers above the videoplane. How do you get the blurred particles to fly in front of and behind the un-blurred sphere?
    A few forum posts have touched on this question. For example: But I can't say that I fully understand the solutions being discussed.
    I'm hoping someone can provide an example or point me in the right direction so I can know where to start reading.

    • Sep 06 2013 | 11:11 pm
      there is probably some complicated solution involving capturing depth to a texture and custom shaders, however the simple solution involves using two objects, one capturing post-processed objects, and one capturing normal objects.
      there are two options, depending on your scene and desired results. the first option is to duplicate post-processed objects in the normal node, and the second is to duplicate normal objects in the post-processed node.
      either way, for the duplicated objects, you simply need the geometry captured with no materials or lighting, and @color set to 0 0 0 0. this will provide proper occlusion in the rendered textures.
      finally, you can simply alphablend the two textures using's. the order the videoplanes are rendered is important, and controlled via the @layer attribute.
      i've attached a basic example using the first technique, and modified the party-lights recipe with a rendered using the second technique.
      experimenting with the videoplane @blend mode will give different results.
    • Sep 09 2013 | 1:56 am
      Cool. Thanks Rob. That's a clever solution. I assumed that this would require a custom shader but it's nice to see that it does not. Although after reading Andrew's shader tutorial I'm now inspired to begin exploring shaders anyways!