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# 1 16-09-2005 , 02:07 PM
ryuhayabusa13's Avatar
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Stuck on tutorial Dynamic explosion for VFX

Hi
I am using maya 6,5 and recently was doing the expl0sion for vfx tutorial found in archives which was done in maya 4.5 .I thought i would be a pretty good introductory tutorial before going into the other newer 6 part Explosion tutorial.

I created a spaceship, cut it into pieces with the "detachSeparate" mel script as explained in the tutorials, and followed the instructions perfectly up to the part where i created all the parts of the ship into rigid bodies.

Then i went and created the Radial field "boomer as described, set the keys of magnitude on the 3 frames 19-20-21 as described, but then something really weird happens.

When i set the key of magnitude 120 at frame 20 as described on the tutorial and then move to the next frame (21), maya takes a long time (almost freezes) then finally at key 21 i set the other key back to 0 as explained on the tutorial.

I got this warning message

Warning: Rigid Body interpenetration occurred between 'debris011' and 'debris011'.

then finally i go to play back from the beggining , at first it starts, kinda normally detaching, but slowly freezing as it gets to frame 20 . finally i stop and play back again. And right at frame 2, the ship pieces are blown apart far far away.I checked all the keys to see if i had by mistake set additional keys anywhere, but i can't figure out the cause of this problem.

If any one has the time and patience, and kindness to take a look and see if there's something I have overlooked, it would be greatly appreciated. I know i am asking for too much , but i'll keep trying, any little bit helps.

Thanks for reading.

p.s. my computer also has decent ram, processor and video card, so i don't believe that's the cause for this particular problem.

Attached Files
File Type: mb dynamic explosion vfx exercise.mb (112.9 KB, 386 views)

"It is Difficult to understand the universe if you only study one planet"
-Miyamoto Musashi-

Last edited by ryuhayabusa13; 16-09-2005 at 02:14 PM.
# 2 16-09-2005 , 06:36 PM
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The warning: "Warning: Rigid Body interpenetration occurred between 'object' and 'object'." always happens when you have collisions turned on.

It is nothing to be worried about unless you are doing some very detailed work.
At the speed those pieces are going, even if one flys though the other, you'll never see it with all the motion blur.

In that tutorial I do not cover collisions, because as with most tutorials, we take you part of the way, the rest is trial and error on your ownuser added image

My 6-part tutorial covers ways to speed up your preview process by using simple tricks like telling the rigid pieces to only use a bounding box of CUBE as its object space, so that way the math is VERY easy for Maya to calculate so you can see your shot timing, and debris effects better in preview modeuser added image

Check the docs and do your research on how to speed-up that simulation by searching for rigid bodies, and ready EVERY tip in the docs.

Trust me, the answer is thereuser added image

You are doing everything right so far.
Good luck!


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com
# 3 19-09-2005 , 04:56 PM
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Sorry i wasn't able to reply right away since the internet was down all weekend at my dorm. Thanks a lot for taking the time to help me with this.

I am just curious since I come from a traditional animation background. On the key frames, on traditional animation frame 1 would be let's say when the explosion starts and then the extreme (which is the last key) would be 150. Well I know it's the world of 3-d animation things work diferently,I am just curious that then at frame 21 the setting going back to 0 when just one frame before it was 120 ,based on traditional animation perspective, wouldn't that make it then go back to it's original pose?

Dynamics is pretty cool, but i need to take more time and understand how it works, so I'll continue with the tutorial and keep trying and see what happens. Thanks a lot again for reading and I am looking forward to starting your next 6 part tutorials. ^_^

I'll post my final results to show how everything worked out. By the way, I was Rolling , when you said "maya doesn't have a create dinosaur button yet"


"It is Difficult to understand the universe if you only study one planet"
-Miyamoto Musashi-
# 4 19-09-2005 , 07:35 PM
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Hey man! No problemuser added image

The reason for setting a key for the emitter at a high value (or any value other than zero for that matter), THEN, one or more frames later, keying it back to zero is very simple:

(my physics will be wrong here, but the idea is the same)

Think of a particle emitter like the light bulb in your dorm room.

Your light bulb is a particle emitter just WAITING to emit particles of light in all directions.

Your room, and the earth it resides in, has a default gravity value.

(In our case, we must ADD gravity to the scene, but that is easy.)

Anyhoo, you enter your dorm room, and you flip your light switch so the light turns on.

What happens? Light emits in all directions REALLY freakin fastuser added image


Now, what if you could control every aspect of the light that gets emitted from your dormroom lightbulb?
(amount, color, intensity, speed, direction, etc.)

In Maya you canuser added image

For example, say you just want to flip the switch and you want the light to only emit for a fraction of a second, BUT, still keeping the same intensity, color, amount, etc.

Well, thats what the 2-keyframe keying example above does.

You key the emitter so the lightbulb shoots a small burst of high intensity light very fast, then key it so it stops emitting, then you get to play around with the light that got shot outuser added image


Another way of looking at it is like turning the water faucet wide open, then shutting it off really quick.

The water that got shot out is still alive and swirling down the drain, but in our case, we caught it in a cup so we can use it for other purposesuser added image

Make sense?

Lemme know!


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com
# 5 20-09-2005 , 01:14 AM
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Totally. Now that makes sense. I understand the power behind the chi flowing in the universe LOL.

I'll get back with my final results in a few days. I am currently working on my thesis storyboards and my final film due in april. BTW I saw your portfolio at your site, I know you probably hear that a lot, but it's pretty impressive.

I hope to reach your level someday. Now back to my training....

Thanks a whole bunch once again man^_^


"It is Difficult to understand the universe if you only study one planet"
-Miyamoto Musashi-
# 6 20-09-2005 , 04:23 PM
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Thanks!

...but my portfolio is not online?

When did you see it, just curioususer added image

Because my NEW porfolio site is being built as we speakuser added image


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com
# 7 20-09-2005 , 08:00 PM
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Sorry, I misused the word, I was refering to your resume. Isaw the pdf file at the frontpage. But I definitelly would like to check out your work when your site remodeling is done.

I need to update my portfolio as well.


"It is Difficult to understand the universe if you only study one planet"
-Miyamoto Musashi-
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