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acceleration with motion keyframer

Posted: 29 Oct 2018, 12:47
by Catriona
Hi everybody

I hope this isn't a really basic question. I have an eagle flying from the distance towards and past the "camera", so obviously it should get bigger as it comes closer. What I can't figure out is how to make the pace of change accelerate as it comes closer. The spline option always seems to want to ease out, not in. I tried using the Z option but I don't think it affects the pace of change. What am I missing?

thanks

Catriona
ps this is what I'm working on, deadline getting very scary... http://lanntair.com/events/event/tha-th ... m-inntinn/

Re: acceleration with motion keyframer

Posted: 29 Oct 2018, 13:11
by slowtiger
I think it just depends on which values you use.
I did this test in a 2000 x 2000 px project. At start I set Z position of "eagle" to 1000, at end to -900. (Set to -500 first, then correct position and increase value, because otherwise position is set far outside of project.) I used 2 keys and linear interpolation only.
adla.gif

Re: acceleration with motion keyframer

Posted: 29 Oct 2018, 13:23
by Catriona
lol, your eagle is magnificent. I had gone from 1000 to 0 so all the good action must be in that negative range. thank you!

Re: acceleration with motion keyframer

Posted: 01 Nov 2018, 10:38
by Peter Wassink
the secret is in the Zcamera value , which you can set in the resources tab of the keyfraemer.

a lower value will get you a more extreme perspective of the camera.

in these examples...
at value 10000 it is extremely tele-lens so hardly any movement on a 1000 pixel z-move.

but on value 100 the movement is really strong on the exact same 1000 pixel z-move value in the position tab.
keyfr1.png
keyfr2.png
keyfr2.png (93.06 KiB) Viewed 14727 times

Re: acceleration with motion keyframer

Posted: 01 Nov 2018, 11:15
by slowtiger
Woah, never noticed that setting. It's not referenced in the manual, am I right? Does anybody know a rule of thumb to translate those values to 35mm lens lengths?

Re: acceleration with motion keyframer

Posted: 01 Nov 2018, 15:03
by Peter Wassink
slowtiger wrote: 01 Nov 2018, 11:15 Woah, never noticed that setting. It's not referenced in the manual, am I right? Does anybody know a rule of thumb to translate those values to 35mm lens lengths?
not sure if that is even possible... in any meaningfull way
though maybe you could reverse engineer something with the use of a series of photos of a row of pole's in one-point perspective shot with different known
focal lenghts?

since all '3D' in tvpaint is a big cheat, i'm pretty sure it just comes down to eyeballing it.

Re: acceleration with motion keyframer

Posted: 01 Nov 2018, 15:34
by D.T. Nethery
Peter Wassink wrote: 01 Nov 2018, 10:38 the secret is in the Zcamera value , which you can set in the resources tab of the keyfraemer.

a lower value will get you a more extreme perspective of the camera.

in these examples...
at value 10000 it is extremely tele-lens so hardly any movement on a 1000 pixel z-move.

but on value 100 the movement is really strong on the exact same 1000 pixel z-move value in the position tab.

keyfr1.png
keyfr2.png
TVPaint Developers, please note:
Peter's post should go into the User Manual immediately ! This is very helpful to know and isn't referenced in any tutorial or page in the user manual that I am aware of.