Particle Tuner Conditions

[BeneZ]

Hello,

I would like to delete particles within a certain random distance to a mesh and also based on other conditions.

- When I want multiple conditions (not only two) to set, which should be "OR", how to do this?
For example: delete when it hits "object A" or "object B" or "age is ..."
The interface only lets you set two things in comparison, which is strange to me.

- Can I combine multiple meshes (placed at different places in the scene) as one object and the ParticleTuner will consider each of the geometries faces, or do I have to create one condition for each separate object?

Thanks

[Svetlin.Nikolov]

Hey hey,

Nested OR-s like you did are fine - doesn't really matter in what order they are listed.

As for the Distances - you can use one condition only if you have one node in the scene - e.g. if you Attach several editable polys into one and they become one node - all of them will be used in the same condition. BUT, if you need the geometries to be separate nodes in the scene, you need several distance conditions as well.

Cheers!

[BeneZ]

Thanks, it means, because I have used 2 distance conditions here is the reason why "distance" did not work at all?
And I would have to create a second Particle Tuner for the second distance, right?

[Svetlin.Nikolov]

Hmmm, so the conditions say:
- if the Age is above 200-300 seconds - this is huge - could this be the problem? This is not in frames, so it would handle a change in FPS.
- or if the distance to Box Maximum Expansion Bottom is more than 1-17 voxels - so this will work for distant particles
- or the distance to Box Tuner Left and right is less than 2.5 voxels - so only very close particles will be affected - beware that you might need to increase this a little eventually.

Sooo I bet on the Age being toooo high

[BeneZ]

Okay
- so the age is not in frames like I thought, it is in seconds depending, which means the frame is depending on the frame rate (very unusual in CGI to measure in seconds, not frames!)
- the distance is not using the units, instead voxels, which I can't measure. or is there a Voxel Measure Tool? normally I take a cube as unit reference, but what to do with voxels?

Couldn't you add descriptions to these fields, which explain all that essential details like units? I did not see it even at the documentation (and if it's nested there, it doesn't help for someone who looks for quick help there)

Thanks

[Svetlin.Nikolov]

Oh, these are some of the Phoenix basics, so we gotta make sure everyone understands them.

In this particular case, check it out:

Here you can see the size of a voxel in the grid - it's on the grid's edges:



You can also use the Graph Cells option in the Preview rollout to make it look like this:

[Svetlin.Nikolov]

So the distance of the Tuners are in Voxels for performance reasons, or it would measure slower. Check the Value Expression Item help here: https://docs.chaos.com/display/PHX4MAX/Particle+Tuner

There is also a link to the page with Particle Channel Ranges in Phoenix - this is also a very important info that you will need when you are doing advanced stuff: https://docs.chaos.com/display/PHX4M...Channel+Ranges

Related to this, then using Grid channels in a Value Expression, you need to be aware of their ranges - here they are: https://docs.chaos.com/display/PHX4M...Channel+Ranges

Hope this help!

[BeneZ]

Thanks,

- is there a way to delete an expre3ssion from particle tuner? (I had to delete the complete node)

- is it correct, that only colliders need to be visible in the viewport, everything works also when it is switched off? (just to be sure that I can turn things off for viewport)

[Svetlin.Nikolov]

Hey,

Expression items are just replaced so the expression can never be invalid. So right click on the parent expression of the one you want to delete and see what Replace options you get. Undo works, so try it and get a feel for it.

As for scene interaction - by default Phoenix interacts with everything in the scene. Unless it's hidden. But these are just the defaults of options you can change any way you want. Check the Scene Interaction rollout:
- If you uncheck Exclude Hidden Objects, the simulation will not ignore those.
- If you switch from Include list to Exclude list, you can hand pick all interacting objects. Note that this means you must pick geometries, you must pick Sources, Tuners, forces, etc.

Cheers!