I’d like to have particles emitted from the surface of a sphere at ‘equal’ speed regardless of the sphere’s speed or direction. So if I killed the particles at a certain age, they’d form a spherical sheath around the shpere (regardless of the sphere’s motion). Is this possible?

Thanks
Mark

Can you go into more detail about what trying to accomplish? There might be a different way because the way you’re asking isn’t really possible because of the moving object.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC

Thanks.

I have an object in motion and I need two streams of particles emitted from it - one in the direction it’s heading and the other directly behind. I think I could script it if the object was moving in a straight line. The trouble is, it’s moving along a curved path and the mathematics is beyond me.

I still only have a vague idea of what you’re attempting. Can you ellaborate more? Maybe add some screen shots?

And are you only stuck on setting the speed for the particles?

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC

Here’s a though, that may work if it is not a LARGE scene...Move everything BUT that object.
You get the illusion of your sphere moving and the particles act like you want.

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion

I’ve attached a file. The sphere is moving and dragging along the particles. If you delete the sphere’s position animation - that’s what I would like to be moving along.

Thanks
Mark

	Attachment
motioninheritance_001.zip

How about making a copy of your sphere then move the path % keyframes -15 so the copy starts moving first. You may need a different number, 10-15 was a good offset for the scene you uploaded. Then replace the original sphere with the copy in the position object op and speed by surface. You can then hide the copy.

This will offset the particles position so they don’t look like they’re dragging behind.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC

There’s still the drag that draws out particles behind the emitter, but that solves the centring problem great.

I appreciate the help. Thanks.
Mark

Try this out:
-Assign a uv planar map to the sphere
-Add a gradient ramp to the sphere’s diffuse so that white is at the front and black is at the back
-Check speed by material in your speed by surface op
-Increase the speed to 50 or so

This will make the particles emitting from the front of the sphere move faster than the ones in the back and compensate for the object’s movement. You might use this along with the way I listed above.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC

That is an extremely good idea. I’ll try it out.

Thanks!
Mark

If you want to get a little more involved with it, you can use Krakatoa. You can use the demo version of Krakatoa to make particle caches which you can then do pretty much anything you want to. You can add modifiers to deform it, remap the time, move it around so it’s in local space. This way will give you the most accuracy.

Mini Turorial:
-Setup your particle animation at the origin with no path movement
-Cache out your particles, they have some good tutorials on that site above (you need the position channel saved)
-Load the cache into a PRT Loader
-Give the object the path constraint and link the PRT loader to the object
-Turn off your old pf source and create a new empty one with just a Krakatoa PRT Birth, Krakatoa PRT Update, Delete, and Display operators
-Add your PRT loader to the PRT Birth & PRT Update ops and make sure the position channel is checked in the PRT Update op

Now that the particles are moving in local space, they all have the same speed even if they’re animated through world space.

3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC