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visualboo
07-31-2009, 05:21 PM
I have a simple animation with an object animating from point a to point b. It moves kind of quickly but I'm having an issue where the fire is actually simulating in front of the object. It looks like it might be about a single frame distance.

Does anyone know why this is happening? And is there anything I can do to stop it from happening?

cheers

visualboo
07-31-2009, 05:29 PM
Example attached

JohnnyRandom
07-31-2009, 05:52 PM
Wow that is odd!

What are your Simulation Steps set to?

Nice Flames ;)

visualboo
07-31-2009, 06:01 PM
Ah only 1. I'll play with that setting a bit. Thanks for the input.

visualboo
07-31-2009, 06:46 PM
The help docs make that setting seem like it would fix this but no such luck.

JohnnyRandom
07-31-2009, 09:47 PM
Yes, typically fast moving objects need more Sim Steps for better accuracy.

You don't happen to have a hidden teapot that is in the object source by any chance, do you?

And

How fast is that Teapot moving? How many frames until it completes the circle?

RFX
07-31-2009, 11:43 PM
Your object emitter velocity might also be coming into play here , since it's moving forward, it might be adding forward momentum to the actual smoke.

Glacierise
08-07-2009, 10:09 AM
Yeah, Fuentealba is right. In your source, in the velocities parameters, you have 'object's' - reduce that ;)

visualboo
08-07-2009, 02:47 PM
Thanks for the replies guys. Sorry I'm an XSI guy using fume for the first time :)

I have velocity set to 0. Though it didn't seem to have any effect. I also upped the simulation steps to 5 with no effect.

I attached the scene if anyone is willing to check it out.

cheers

RFX
08-07-2009, 02:51 PM
Thanks for the replies guys. Sorry I'm an XSI guy using fume for the first time :)

I have velocity set to 0. Though it didn't seem to have any effect. I also upped the simulation steps to 5 with no effect.

I attached the scene if anyone is willing to check it out.

cheers

Are you running Max 2010? I'm trying to open your scene in 2009 but not being able to.

visualboo
08-07-2009, 03:03 PM
Ah yes sorry. 2010

JohnnyRandom
08-08-2009, 09:51 PM
Well first, be kind, post a sample scene with local/no paths ;) waiting a dogs age for my machine to figure out that they don't exist on our network...

Uh umm... your teapot... or should I say Fume is working as it should, it is your teapot that needs to layoff the Starbucks Triple Espresso's :)

I slowed your teapot down from 24 frames (one time around the path) to 200 frames, the issue is now apparent.


http://www.4rand.com/TEST/Cgtalk/FumeFX/BadTeapot.gif

You just happen to be rendering a frame when the teapot is coming back instead of it apex forward. Or it happens that it is so quick that it will always render the teapot on the trail end of the inner loop.

visualboo
08-09-2009, 03:41 PM
Sorry about the paths. And thanks for taking the time to look at this.

Nice find btw. Looking at the keys, the interpolation was getting set to bezier which made the tangents fail.

Before:
http://www.genecrucean.com/misc/speedObjectTester_Before.jpg

After a quick scale:
http://www.genecrucean.com/misc/speedObjectTester_After.jpg

Even after setting the keys to linear interpolation and cranking a few settings, it still seems to have this effect. Is there a known object speed limitation with Fume?

JohnnyRandom
08-10-2009, 09:37 PM
I recreated your scene albeit for the spiral (not sure how you acquired its motion), and I cannot seem to replicate the issue.

My guess is something buggy in the scene file.

Below this is at 3 sim step and it is noticable by the stepping close to the teapot but anyway...

http://farm3.static.flickr.com/2626/3808699053_e435ef5a40_o.jpg

visualboo
08-10-2009, 11:17 PM
Odd. Thanks for taking the time to play with this a little. I'm still experimenting.

JohnnyRandom
08-10-2009, 11:35 PM
I for the life of me could not figure it out, so I opted to try and rebuild it to see if the issue reoccurred. It is odd because I see no reason why it is behaving like that. I guess it could be as simple saving your settings and creating a new grid (didn't try that).

JohnnyRandom
08-11-2009, 02:16 AM
Ya know I just thought of something I seem to remember your animation starts on frame 1, does you fume setup begin on frame 1 as well? I can't check it at the moment. it just something that occurred to me.

JohnnyRandom
08-11-2009, 04:43 PM
Ahhh IT WAS! Start frame was set to frame 0 it needs to be frame 1, man if I had a dollar for everytime I have overlooked the obvious in FumeFX, well... lets say... I could buy my wife a real nice dinner with wine :)

visualboo
08-13-2009, 05:13 PM
My output and playback ranges are 1-100 though. Interesting thing to keep in mind though. Does that really offset everything like that though? Seems to me it would just not calculate on that frame.

JohnnyRandom
08-13-2009, 08:43 PM
It is odd, agreed. In the Playback Range Section below the 'Play From' and 'Play To' spinners is the 'Start Frame' spinner, that was the culprit parameter in the sample file you posted. This is just a guess, i think they did it this way so it was easier to offset your start times. I seem to recall this bungling me up in the past...Anyways I hope all is better now:)

visualboo
08-19-2009, 02:50 PM
Actually it was extremely helpful. Thanks for the time John.

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