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FUoSS
03-24-2008, 11:29 PM
I have been wracking my brain over this for weeks and will be greatful for any suggestions. Basically the final effect is a machine gun from behind the camera shoots a series of bullet holes into plane in the distance. Blood flows out of these bullet holes towards the camera and hits an invisible plane causing the blood to splat into a shape forming letters.

I am not very seasoned in scripts or in dynamics in general, so I have been taking a sort of brute force angle at this using a series of collision objects and fields. The closest I have gotten so far is using the following technique, results are far below my standards.

I am using a plane with an alpha map to emit enough particles to create each letter which will eventually be formed. I have a decent blood shader and am satisfied with the look of the final letters formed from blood (this can be improved upon later).

example blood letter
http://pub.fuoss.net/cgtalk/vsplat.jpg

My problem is getting the particles to pour out of the hole, and "splat" into the final shape. Thus far I have tried the technique of sucking the already formed particles back into the hole, with the plan of playing the frames in reverse to get the intended effect. It always ends up looking way to calcuated and I cannot get enough variation in the first few frames to get teh simuation of it splatting into place. It looks more like the blood gracefully flows out perfectly forming the final shape.

Once the blood splats into place, it will begin to slowly drip down the screen, this will be very subtle. I want to add some gravity with dropoff and maybe even some per particle attributes to have some actual dripping in areas where you would expect to see it, but I think what I am really missing here is that some sort of "trail" or "streaking" would be expected as it moves down. Always leaving a hint of where the original splat had occurred as the blood mass slowly flows downward.

dripping test .mov file (http://pub.fuoss.net/cgtalk/vblood_driptest7.mov)



I am not as concerned about the dripping part, I think when I get there I can improve upon that myself. Is there a more logical way to go about projecting the particles out of the bulletholes and creating that final "splat" effect. Is there a way i can create this simulation the same way it happens, instead of trying to work in reverse? Any ideas would be greatly appreciated. I will continue to post updates as I try different techniques.

geonak
03-25-2008, 11:34 AM
did you try to use goals ? i would say go to real flow but since you're into particles

scripting may help a lot but since you seem not to like programming so try goals

olcho
03-28-2008, 04:41 AM
A more controlled effect would be if you use a texture emission rate. For example, you can make a simple nurbs plane (or poly), paint a white letter V or whatever you want to write and apply that texture to an emitter that emits from the plane. You'll only have to play with the timing of the start of the emission, make it short, for may be 2-3 frames, emit a lot of particles with no speed.

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03-28-2008, 04:41 AM
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