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Cloth arbitrary vel field

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Has anyone successfully gotten the "External Velocity Field" in the Drag tab on a cloth object to work? The docs indicate: "You should not use the Wind Force DOP or any of the other forces in DOPs because they will generate inferior results compared with the Air Drag model." So I've been trying to pass in a velocity volume, and dutifully using the Drag External Velocity Field slot as instructed, but no matter what I try, I can't get the cloth to respond.

At first, I thought all I had to do was reference the velocity volume directly from the EVF slot, with some sort of syntax: /obj/volumeObject/volumeVelocity1:vel or some such. Failing to get that to work, I searched for example files, and all I found was a Wire Solver example (the Wire setup has a similarly named EVF slot), wherein the velocity volume was loaded into the DOPSolver via a SOP Vector Field DOP and attached to the wire. The EVF field was left at the default "vel", and the velocity volume was named appropriately (vel.x, vel.y, vel.z). But trying the same thing with the cloth solver still gives no response.

I've attached a simple file that indicates what I thought the correct setup should be. What am I doing wrong here?

test_v2b_clean.zip

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I contacted Sesi support to ask how does it work. They told me that there's a bug and they will inform me back when the bug is solved. So i will also post it in here.

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Sesi contacted me back to inform that the cloth vel external force have been fixed in the build 12.5.396.

They also sent me an example file showing how it works: ClothInVelocityField.hip

Very amazing support!

Edited by Fabiano Berlim
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Cool nice one guys. This example uses pyro sims in the dop net to create the vel field. Is there a way to bring in data from SOPs such as a simple bounding box to define an area where you want velocities to exist? 

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I managed to bring in my vel field from outside by using a smoke object then a merge with the cloth inside dops. Under the "External Velocity Field" in the cloth object I entered "vel"

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@soomld would you happen to have an example scene for this? Or even a screen shot? I've been try to do exactly that all day but I've either been getting errors or just nothing.

 

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Hey, I'm trying to do this too… to use an external velocity field to influence my cloth…

If I input the path to my SOP velocity field in the Smoke Object Initial Data Tab and merge that with the Cloth Object, although the vel field gets picked up it's not updating/animating… So I don't understand how to merge an animating external velocity field into a Cloth Object.

Would be grateful if anyone can enlighten me on this.

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OK, so managed to work it out…

Here's a grab of the setup that seems to work…

5de622b2ef0f7_ScreenShot2019-12-03at08_53_24.thumb.png.cda3c1cf460e4ff47099df563d1b742a.png

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