timewarping imported bin

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rebusbakery@gmail.com
Posts: 32
Joined: Thu Jan 05, 2012 11:49 pm

timewarping imported bin

Post by rebusbakery@gmail.com » Thu Oct 15, 2015 6:13 pm

I am using a scene timewarp in Maya to do a varispeed effect that goes from normal to super slow motion and back. Was hoping that the imported bin mesh would time warp along with the rest of the scene. It almost does...

The mesh interpolates but it is steppy during the slow parts so it is interpolating between the steps, just not correctly. There is constant movement on the mesh during the slow parts but every n frames it jumps, as if the interpolation is getting 75% to the next cached frame but has to jump to make it that last bit.

Is there a setting or method that will correctly interpolate the velocity of the mesh to be able to slow it down below the frame rate it was cached at without the jumps? It is so close to working.

If not I was going to raise the fps in MentalRay hoping that the imported sd animation from maya will stretch properly for the sim, cache at the higher frame rate, and then reimport mesh, but I am not sure how to handle the frame conversion and subsequent scene timewarping in maya.

Playing with the Motion Blur Multiplier on the realFlowMeshSource node has an effect on but unable to eliminate stepping, higher values makes the stepping more obvious, and a value of zero eliminates all interpolation. A value around 2.25 is the best so far but still stepping.

btw- A test of timewarping an imported particle bin works fine.

rebusbakery@gmail.com
Posts: 32
Joined: Thu Jan 05, 2012 11:49 pm

Re: timewarping imported bin

Post by rebusbakery@gmail.com » Thu Oct 15, 2015 6:15 pm

quick thought: could it be that the topology of the mesh is changing (drops forming and merging) therefore cannot be interpolated even though the velocity can be?

rebusbakery@gmail.com
Posts: 32
Joined: Thu Jan 05, 2012 11:49 pm

Re: timewarping imported bin

Post by rebusbakery@gmail.com » Thu Oct 15, 2015 6:24 pm

following up: changing the frame rate in RF has no effect on the duration & timing of the imported .sd file. :(
so even though the frame rate is changing from 24 to 480 fps, the .sd animation is still the same number of frames. Will have to do the slow down in Maya... or not. Trying the Retiming Tool in RF first.

Got something that works. The retime in RF was the first step... extended the sim x5, then put a multDoubleLinear between the time1.output and the realFlow mesh loader timeIn attribute with the same x5 multiplier. Now the timewarp works just fine.

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LuisMiguel
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Re: timewarping imported bin

Post by LuisMiguel » Mon Oct 19, 2015 9:16 am

Hey,

Where are you changing the frame rate?. In the Preferences?. Keep in mind that any parameter you change in preference will be active for next new scenes but not for the actual. If you want to change the fps for the actual scene you will need to change the fps in the simulation options.

luisM.

rebusbakery@gmail.com
Posts: 32
Joined: Thu Jan 05, 2012 11:49 pm

Re: timewarping imported bin

Post by rebusbakery@gmail.com » Mon Oct 19, 2015 3:13 pm

Changed in simulation options. Turns out .sd files do not time scale based on fps as they are keyed to frames, not time. Apparently alembic .abc files will time scale when the global fps is changed, but I am not getting the deformations when importing .abc files.

In the past I have had success changing the fps of a scene and having everything change along with it, but that was for things keyed in RF.

So I am still doing time warping in Maya. Fixed the skipping and the .sd locked to frames by extending simulations in RF with Retime tool and putting a multiplier on the input time of the bin file importer in Maya to compensate for the extra frames.

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