Special notice to all federal, state and/or local government (administrative and law enforcement; national and international) agencies who have been visiting my site because you found the letter-number combination C and 4: This is a tutorial on how to use a 3-d graphics particle and physics simulator; it just happens to be called C4. This program and the following tutorial have absolutely nothing to do with the high explosive! You can find the program and details about the program at this link: http://www.informatik.hu-berlin.de/~goetsch/C4/.
I'm working on a scene that takes place on Arrakis and was trying to find a way to trick LW's PFX engine into creating particle emitting particles (particles that would spontaneously create particles without a collision event) using C-4. It didn't work because C-4 is a displacement plugin and the PFX engine reads only the bounding box position of the surface or vertices even if I activate the emitter after the C-4 event. Anyway, as a side effect, I did find a pretty neat way to make tertiary particles.
Create a sphere* (tessed or poly) with default sides and segments and cut it off below the Y axis. The actual dimensions of the sphere depends on your needs. I went with 500mm X,Y,Z. Subdivide the polys with Shift+D (not Tab) with the Faceted method and 0% fractal (you'll jitter the points later). Subdivide 3 or 4 times if you need lots of debris. Don't subdivide it more than four times unless you have a fairly muscular system. Kill the polys (altogether: "K for kill"). Jitter (Shift+J) the points radially. The size of the jitter should correspond to the size of your sphere: 1 meter sphere, 1 meter jitter. Use Volume select to delete any points that fall below the Y axis. Under the create tab click Points to Polys. If you divided the sphere 4 or more times you will have a few minutes to get a cup of coffee. At least I did. Give the entire object a surface name or select groups of points and give their surfaces a name. Save the object and create a square ground-plane (mine was 20mx20m and flat) if you don't already have one. The ground plane will be the collision object for C-4.
Bring the sphere and ground-plane into layout. Apply C-4 and tweak to taste, but make sure to select ground collision with the appropriate ground level and make the ground plane the collision onject (all this is under the C-4 collision tab). If you don't have C-4 you can get it via Flay. C-4 is easy to use, gives reliable results and is free. Get it before the authors wise up and realize they could take a lot of business away from Dynamic Realities. I'd talk about the specifics of using C-4, but the docs that come with C-4 are very good.
The advantage of this trick is that once a C-4 poly stops bouncing, it stops bouncing. Unlike in LW's PFX engine where the poly will "run in place" after it stops bouncing. Furthermore, since these are single point polys you can edit their surface attributes and adjust render properties. When you use this little trick to augment hypervoxels (and Particle Illusion if you have it) you can achieve effects that are beyond plausible. By adjusting transparency, specularity, adjusting pixel thickness, ramping dissolves and/or adjusting the number of polys you can get some really cool tertiary effects, i.e. fine dust, gravel, tumbling shockwaves or powdered glass from a window breaking.
*I started off with a flat plane, but, evidently, C-4 needs to have a range of Y values in order for single point polys to react. With a flat plane the particles only moved in the X & Z axes or dropped through the ground plane..
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