View Full Version : collision not working in "real time" - help

02 February 2008, 04:09 PM
Hey I've got a difficult problem.

I have a box which is moving up and downward.

When On the surface of the box are spawning planes.
When they "leave" the box I want them to die... it all works fine when I animate it... but since I need this to work in realtime... particle flow is not deleting the planes.

Scene file 30 kb (3dsmax 2008) (

Another problem is, that I wanted the texture - or the type of the particle which is spawned of the surface - to change depending on the position of the box...

I thought I add some sort of fields into the "world" so when the box passes a field it spawns different particles... but since collision is not working - i'm clueless.

Here's a picture:
the grey box spawns the green planes.
The box is attached to the camera which can move up and down and to the sides when you move your mouse.
When the planes touch one of those purple planes - they die...

but they don't since particle flow is not doing it in real time...

thanks for your help.

02 February 2008, 08:52 PM
I am not sure that PFlow is able to do this by default. It is not really designed to work in real time. But it is actually very simple to do with Box3 ( (

As for the texture issue, you could create a material with a scripted Controller to adjust the material based on the box position. Or you could get a bit more in depth, again with Box3.

02 February 2008, 01:12 AM
I haven't checked your scene but you could try lowering the integration step to gain some accuracy in the collision department. Yep real-time not really super functional with pflow.

02 February 2008, 08:42 AM
I checked the scene, and between that and the original post, I assume he means the ability to move the stuff around in the viewport and see the feedback in realtime, hence the fact that it works when animated (keyframed), but not when in 'real time' (not keyframed, just moved around). As such, the stepping wouldn't (and doesn't) make any difference. That is the first thing that came to my mind until I read the part about it working when animated. Correct me if I am wrong on this.

But this is something that is possible within Box3 by simply testing to see if the particles lie within a mesh (a box in this case) and deleting any that do not.

02 February 2008, 04:43 PM
Ah, I think I understand, so a "real-time viewport update" or instant dynamic feedback of sorts...that would be nice and yes integration step wouldn't help.

03 March 2008, 12:18 PM
thanks to all of you for your help.

Unfortunately the Box 3 solution of deleting the particles when they leave the box didn't really work.
I set it all up - and if worked fine... but it didn't once I reloaded max... is this a demo restriction?

Thanks for the tip anyway... there are a lot of neat features in these tools.

We kept it the way it was then... because otherwise PF would spawn an endless amount of particles if you don't move the camera.

Thanks for your help

03 March 2008, 04:16 PM this a demo restriction?

Most likely it is. There are a number or restrictions on the demo version. It works fine on my end.

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03 March 2008, 04:16 PM
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