View Full Version : Bug reports in Maya 2011 dynamics

04 April 2010, 08:11 PM
Thought Id create a local thread on suspect bugs in dynamics Maya 2011.
First off my suspect bug is using a surface emitter for fluids. When emitting speed only, and inherit velocity is on the vectors fall downwards for no apparent reason. Adjusting gravity in the fluid shape doesnt change it and animating the mesh shape doesnt seem to apply any directional force anywhere except downwards. This feels like a bug to me.

04 April 2010, 08:20 PM
It works for Duncan.. hehe

I may have noticed something missing in my tests. I'll post here if I come up with the solution.

04 April 2010, 11:09 PM
It works for Duncan.. hehe
I may have noticed something missing in my tests. I'll post here if I come up with the solution.

Unlikely but it may just be a mac thing.

04 April 2010, 04:53 PM
Auto Resize Fluids:

- fluid is not emitted at the emitter's position
- fluid emission starting after a few frames of "handles"

04 April 2010, 05:35 PM
When emitting speed only, and inherit velocity is on the vectors fall downwards for no apparent reason.

Make sure normal and tangent speed are both zero. Also the object needs to be keyframed... playing back in interactive mode while dragging will not not work for velocity inheritance( unless one is dragging vertices ).

I've attached a simple scene that shows the velocity inheritance. The fluid is highly damped so one only sees the emitted velocity. Does this work OK for you?

Also note that I turned on motionStreak, which better handles fast moving objects. (the emission is interpolated across the object motion) However it still works without this.


04 April 2010, 05:44 PM
Yep works beautifully.

04 April 2010, 06:51 PM
Thanks Duncan, you have been speeding up my fluid fx comprehension for years! I think I owe you a few beers at this point ;) Thanks again!

05 May 2010, 09:18 AM
Could somebody check this scene for me, I have tried and tried to replicate duncan's scene but Im still having problems. Really appreciate the help.

05 May 2010, 06:38 PM
@aiki :
I tried opening ur scene & couldnt figure out whats wrong there ? :(
i also muted ur helix animation & I noticed even in still it affects ur fluid velocity.
then I creating a new scene & It kind off worked for me but meanwhile I encountered another bug & that was if the same helix object emits particle & if u try to advect with the fluid motion then ur velocity of the fluid freezes & it wont affect the way it was working in duncans example.

but when I delete the particle system then it work fines. as if it seems that it switches back to in its working state. for me its a very strange experience. let me know if it happens same at your end.
I am attaching the scene file, plz have a look.


05 May 2010, 09:05 PM
Hey Vik, I checked your scene and you are right, I cant get any velocity vectors while emitting particles but once the particles are deleted you have a working scene again, so in some ways congrats because you have got it working Duncan's way, but I think you have found a bug there too.

Unfortunately I still cant get mine to work. With mine its almost as if Maya is using the bounding box information and not the mesh surface itself. Im really starting to think this is a mac bug.

My method = create fluid, create mesh, create fluid emitter > emit from surface, emit speed etc surely this is the way to set it up.

On a side note, the inherit velocity works well on nParticles as emitter.

05 May 2010, 05:25 AM
Just found an answer to this thanks to Duncan on another thread. If at any stage the transform of the fluid is not at world zero then the velocity vectors are driven in the opposite direction. In my case my fluid container had been translated up 10 units hence the downward velocities. Try it yourselves, move your container and press play.

The obvious workaround is to leave your container at world zero.

05 May 2010, 11:28 AM
Bug 1: This happend in Maya 2011 in two different projects from different people on differnet computers. So I guess, it is a bug.

There is a fluid in the scene and 1 or more directional lights using raytraced shadows. If there is only these lights and the fluid in the scene with no other geometry visible, the lights aren't calculated correctly.

The rendering finishes fast and all you get is a white blotch without any shadows. When there is geometry made visible (also geometry not interacting with the fluid) the lights are calculated correctly.

Bug 2:

There are two scenes, those are identicla from the settings. There just have been made slight changes on the fluid texture settings (frequency/ amplitude). Something that is in any manner connected to color or color settings has never been touched. In scene a, everything renders as expected. In scene b, the fluid renders like a blueish/ yellow play dough mass.Trying everything possible, I found out it had something to do with incandescence (which I didn't use anyway). Fixing the scene was possible by overriding the fluid in scene b with the prerences of scene a. As mentioned earlier, the only change between those versions was a change in frequency of the Perlin Noise texture.

Bug 3:

As confirmed by Duncan, fluids do strange things when fluid lights are used.

Bug 4:

Why did you take these resizable containers into the release, anyway? Far away from the reliablitiy I need in production, it is a toy, nothing more. Do you mean Maya is a several thousands of dollars toy?

To anyone at AD: When I am betatesting a product, I notice bugs like these and file them in, as I expect those bugs. When I buy a product, bugs like these are quite an annoyance. This is the third strange bug in the new Maya fluids I found in 10 days and it means to me "Don't use Maya 2011 fluids". Another annoying thing is nParticles are just as crappy and insuitable for production (at leats if you are working in the commercial business with short timelines etc.) as ever before. Maya 2010 was a laugh. No new features and some software bundeled the majority of people here doesn't need. Maya 2011...a Qt interface that has been badly implemented (maybe because of the needs to keep the MEL heritage) and is slow as hell, new fluid functions that are unpredictable and full of bugs and other dynamics "features" such as nParticles are the same pain as they have ever used to be. Thank you. That's worth the money.Guys these are BASIC functions in dynamics. Basic rendering and lighting, no big magic but even those basic functions seem to overburden your development teams.

Finding bugs like that , I keep asking myself how many people of the Maya dev team have been sacked out during the crisis?

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