Pyro Exprlosion Fire/Smoke Trails

[mr_dreamer]

Hi there,

I'm pretty novice in Houdini.

I'm looking for a way to randomize the fuel emit rate from flying away debris and to fade out the sourcing of the fuel gradually.

Will be appreciate for any help and recomendation.

Thanks,

- Vlad -

[mr_dreamer]

This is a scene file.

destr_box_v012.hipnc

[Filipp Elizarov]

Hello Dreamer =) I prepared a small scene for you.Maybe it will help you a bit and will be an answer for your question about how to add random fuel rate for each piece.In my scene you can increase or decrease fuel rate for each piece in foreach in Sop level or in DOP in gasparticletofield microsolver. )In VOP you can animate fuel attribute or modify it like you want or can immagine (It will give you a very very nice control)

FUEL_FIRE_TRAILS_MY_v01.hipnc

[mr_dreamer]

Thanks a lot Filipp!

Really appreciate your help. Thanks for the example file! Interesting technique!

Спасибо !

[Filipp Elizarov]

You are welcome ! Glad you like it )

[mr_dreamer]

Filipp,

Your explosion rig really helped to me to learn VOP SOP's abilities.

The question is how to avoid gaps in trails if chunks' speed are getting faster.

First I played with sub-steps in DOP network without any success. Then I conjectured that I could use Trail SOP to get geometry samples along their path. It works pretty good. But probably there are some better ways to achieve a similar effect.

FUEL_FIRE_TRAILS_MY_v02.hipnc

[Filipp Elizarov]

You can play with CFL condition and Max Substeps , CFL condition it's a fit between min and max numbers of substeps.And maybe I forfot to append a !!! TimeBlend !!!! sop for RBD pieces at the sop level , because if we don't put it - our geo won't be updated between frames and as a rule it will give us a small gaps in fluids - Always trying to PUT timeblend to your emitter .If you CFL condition = 1 it means if your fluid moving more that 1 voxel per timestep , Solver will use Maximum substep.Value 1 by default is very small for fast explosion you can increase this value to 5-10.

[mr_dreamer]

Cool! Thanks Filipp!

[Sierra62]

That was an incredibly helpful example you put together. The only thing I am slightly confused about is why you used the "add" node prior to "vopsop1"

.

[Castelis]

Hello, thanks for an example. I am using H12.0.683 Aprentice HD learning houdini and I am confused with one thing. Inside DOP Network the rigid body simulation performs as expected, but outside DOP node its spins around in chaos. I am probably doing something wrong. Do you have any suggestions? Thanks, Francesco.

[Filipp Elizarov]

Hello stoof !

Answer for your question is a very simple ) Add Sop added a 1 point to our scene - after we put add to second Vop1 input and inside we Importing the Position of our point from input2 to our vop sop - then we substract position of each point from 1 input from Position of second point (from our single point Pos) it will give us a Vector which we will use a bit later as a velocity attribute for our RBD pieces.

HI Castelis !

1.You can use a Drag Dop node and increase Scale torque value - it will help you.

2.Put RBD Auto Freeze node and play with Angular velocity Scale parameter and with Motion decay. Both of this nodes will give you a good result.

[Castelis]

Hi Filipp, thanks for quick reply and your suggestions. But I think behavior I am experiencing is caused probably by something else. I did a quick screencapture to illustrate. Its the file you provided as a sample. Maybe its some kind of bug. I dont know. Anyway thanks again for your explanations. Francesco.

P.S. Rename .txt to mp4 I wasn able to upload .mp4 extended file for some reason

ScreenCapture.txt

Edited December 1, 2012 by Castelis