original velocity vector with retimer

[hkroeber]

Hi
i am searching for a way to stop a tycache with the retimer but rendering it with the original motionblur.
Is this possible? Perhaps there is a way (like a future button ;-)) to get the original velocity information for a particle when using the retimer.

Regards
H.Kroeber

[tyFlow]

Hmm, interesting idea...right now it's not possible by default because moblur is calculated as the difference between transforms over the motion blur interval. No motion = no moblur.

I'm just spitballing here, but maybe the tyVertexVelocity modifier could be used to save the original motion to a UVW channel (it has that option), then you could do a render-to-texture bake and load that in as a velocity map? Not really sure if it would work since I haven't tried it....moblur on stationary geometry is an unusual request.

[hkroeber]

Hmm, interesting idea...right now it's not possible by default because moblur is calculated as the difference between transforms over the motion blur interval. No motion = no moblur.

I'm just spitballing here, but maybe the tyVertexVelocity modifier could be used to save the original motion to a UVW channel (it has that option), then you could do a render-to-texture bake and load that in as a velocity map? Not really sure if it would work since I haven't tried it....moblur on stationary geometry is an unusual request.

Well...  seems to be complicated. hoped that would be easier ;-)
alternatively i thought about something like a hacksaw in the curve editor. This would be the brute force way.
i think i try your way first (if i understiood it right)

By the way: 9 years ago i did this in thinking particles. back then i was surprised that this worked. Its still online: https://www.youtube.com/watch?v=Fm3iuoItT94
not very impressive in this days but i working on it ;-)

Regards
H.Kroeber

[tyFlow]

Ok, I tried it and it's actually a lot easier than I thought. Here are the steps:

1) In your tyFlow, add a Mapping operator...set mode to mapping from velocity, specify a channel of your choice and set timing to continuous.
2) In your tyFlow, add a Mesh operator and turn off render-only
3) Retime your tyFlow however you want
4) Add a tyVertexVelocity modifier to your tyFlow and choosing velocity from UVWs and specify the channel you specified in the Mapping operator.

Now any frame you render, no matter how it's retimed, will have the moblur of the un-retimed original frame. NOTE: this method only accounts for linear motion, not angular motion, so it's not completely accurate....but that might not matter for your purposes.

[hkroeber]

Ok, I tried it and it's actually a lot easier than I thought. Here are the steps:

1) In your tyFlow, add a Mapping operator...set mode to mapping from velocity, specify a channel of your choice and set timing to continuous.
2) In your tyFlow, add a Mesh operator and turn off render-only
3) Retime your tyFlow however you want
4) Add a tyVertexVelocity modifier to your tyFlow and choosing velocity from UVWs and specify the channel you specified in the Mapping operator.

Now any frame you render, no matter how it's retimed, will have the moblur of the un-retimed original frame. NOTE: this method only accounts for linear motion, not angular motion, so it's not completely accurate....but that might not matter for your purposes.

Yeah.. thank you..
is the mapping information saved into an tycache too ?

Regards
H.Kroeber

[tyFlow]

Yes, mapping overrides will be saved to tyCache data so the idea above will work on tyFlow and tyCaches.

[hkroeber]

Yes, mapping overrides will be saved to tyCache data so the idea above will work on tyFlow and tyCaches.

 Hi i had some issues and now i have the time to check it.. it works with tyflows forme but not with tycaches. today i did a little test with a preset flow and there is the same issue when export it.

Regards
H.Kroeber

[hkroeber]

Yes, mapping overrides will be saved to tyCache data so the idea above will work on tyFlow and tyCaches.

 Hi i had some issues and now i have the time to check it.. it works with tyflows forme but not with tycaches. today i did a little test with a preset flow and there is the same issue when export it.

Regards
H.Kroeber

After testing more i think its the tycache instancing for vray which is not correct. if i set it to meshes it works.

Regards
H.Kroeber

[tyFlow]

Mapping overrides are disabled by default in tyCaches. You can enable them in the tyCache settings.