How would you add an object velocity into a fluid velocity?

[cloudfx]

Hi,

How would you add an object velocity into a fluid velocity?

What I was using was below but I would like to know how the other method would be suggested.

1. calculate velocity from object ( trail sop , point sop (point subtract) or vop sop(point subtract and point cloud to make edge soft or etc).

2. convert the velocity into volume

3. initialize the velocity volume and add to "vel" attribute in dop network (gas calculate , gas vop or gas linear)

Beside above, what else choice do I have for velocity add from an object like inherit velocity from an object?

Edited December 4, 2012 by cloudfx

[fxrod]

Maybe I'm stating the obvious, but couldn't you use the Source Volume Dop directly?

http://www.sidefx.com/docs/houdini12.1/nodes/dop/sourcevolume

[woodenduck]

Sop vector feild dop.

[cloudfx]

Sop vector feild dop.

That is what I was suggesting from the top. I want to see how the other people use object's velocity added to their fluid vel.

[Filipp Elizarov]

Maybe an idea to add Vel through Gas Field VOP and Point Cloud . It works really slow but I think sometimes it can be useful.

add_vel_to_DOP.hip

[anim]

Maybe an idea to add Vel through Gas Field VOP and Point Cloud . It works really slow but I think sometimes it can be useful.

it's much faster to use Gas Particle To Field DOP if you just want to transfer velocity from points like that

or Field Force DOP to make it act as a force since you are adding it anyway instead of just blending/replacing

but in general anything that can modify fields can change velocity, there is plenty of nodes/methods for that, it really depends on usage, use simple and fast ones like Gas Linear Combination, Gas Calculate, Gas Particle To Field for basic transfer and calculations and more expensive ones like Gas Field VOP and Sop Solver for more complex math

on top of that very quick way is to just check use point/volume/rigid velocity for colisions/sources directly on smoke solver which will take care of basic velocity transfer from them

[mdunkley]

Seems like Francisco's suggestion is the current "best practice" (or at least convention) for what you're suggesting - Source Volume DOP using the "pump" preset should do just fine.

Or if you're bored with that you could always use a field force, which works with either volumes or point attributes.

[cloudfx]

it's much faster to use Gas Particle To Field DOP if you just want to transfer velocity from points like that

or Field Force DOP to make it act as a force since you are adding it anyway instead of just blending/replacing

but in general anything that can modify fields can change velocity, there is plenty of nodes/methods for that, it really depends on usage, use simple and fast ones like Gas Linear Combination, Gas Calculate, Gas Particle To Field for basic transfer and calculations and more expensive ones like Gas Field VOP and Sop Solver for more complex math

on top of that very quick way is to just check use point/volume/rigid velocity for colisions/sources directly on smoke solver which will take care of basic velocity transfer from them

Yes, but Gas Particle TO Field needs decent amount of particle in some case which it does not reach to the voxel that it have to do the calculation for vel or whatever field. You can increase the radius of search but sometimes, vector type volume convert from less point amount and use it in Gas Field VOP for more complex calculation or Gas Caculate or Linear Combination for simple calculation would do the job faster.

In some cases, sim with lots of voxel data compare to the scene scale, large amount of particle may take the sim really slow.

What my question was mainly about not technically getting the vel data to dop vel but what kind of method out there for object velocity implementation for emit source but thanks all for attention!

Edited December 10, 2012 by cloudfx