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Philbert
06-23-2018, 02:26 AM
I finally figured out how to do camera tracking in Blender, then send it to LightWave (2018). I used Alembic and just had to make a few adjustments like the camera resolution and frame rate. So I did it, it worked fine on my laptop. So I tried to do the same thing again and my desktop and this time write down all the steps. Everything seems to be working fine. But here's the weird thing. In LightWave the camera seems to be moving fine, but then on frame 88 all the camera rotation settings get flipped to negative, making the camera turn around 180 degrees. Then on frame 176 it flips back. On frame 214 it flips to negative again and stays there. Any idea what's going on? I've tried restarting LightWave, reloarding the saved scene and reloading the ABC file. No luck.

Ztreem
06-23-2018, 03:40 AM
I guess it’s a case when two apps use different rotation math for rotation. You could try to add quaternion booster to the camera in LW and see if it helps.

Ztreem
06-23-2018, 04:54 AM
As Alembic is baked then maybe the quaternion booster method don’t work. I think this is a LW problem as I had simular problems with motion capture files that works and look ok in other apps but in LW you get this 180 degree flipping. You could also add some nodes that add 180 degree to the rotation if the values go below a certain value.

ianr
06-23-2018, 08:44 AM
Phil,
Alembic should get a doctoring soon in LW, (its not up to the Houndini rev)
Therefore I would bug report it, which should get the devs to update Alembic
& stop the flip at the same time with some 'watcher' code.

Philbert
06-23-2018, 12:19 PM
Thanks. Unfortunately I was planning to make a tutorial on this but if it's buggy I guess I can't. Unless I tell the viewers "it might not work". lol

Philbert
06-23-2018, 12:26 PM
OH! I just realized there have been updates to 2018 that I haven't downloaded. Maybe this one in .03 will fix it:

"LWB-3541 Camera imported with alembic flips rotation if we move any other item"

Edit: Oh never mind I already did install the updates and forgot.

jwiede
06-23-2018, 01:56 PM
OH! I just realized there have been updates to 2018 that I haven't downloaded. Maybe this one in .03 will fix it:

"LWB-3541 Camera imported with alembic flips rotation if we move any other item"

Edit: Oh never mind I already did install the updates and forgot.

Hmm, that sounds like they're declaring LWB-3541 "fixed" though it may not have been. Definitely worth a bug report, and worth referencing LWB-3541 in that report.

Philbert
06-23-2018, 02:04 PM
I reported the bug but interestingly before I reported it I realized that my laptop is still on .0.3 So that means they did fix it in .0.3 but then it broke again in .0.4.

jwiede
06-23-2018, 03:21 PM
I reported the bug but interestingly before I reported it I realized that my laptop is still on .0.3 So that means they did fix it in .0.3 but then it broke again in .0.4.

It'd only mean that if .0.3 didn't exhibit the problem, which you haven't stated/confirmed. If you saw .0.3 not exhibit the issue, then move back to .0.3. All current says is .0.4 has bug again.

Philbert
06-23-2018, 03:28 PM
Yeah it worked OK on my laptop and I realized my laptop is on 0.3. So I can downgrade for my own projects but for a tutorial I guess I could just do it in 0.3 and make a note about .04.