POV-Ray : Newsgroups : povray.binaries.animations : Absolutely relative woes : Absolutely relative woes Server Time
23 Jun 2024 23:33:57 EDT (-0400)
  Absolutely relative woes  
From: Dick Balaska
Date: 23 Feb 2020 20:10:18
Message: <5e53227a$1@news.povray.org>
This has me stumped.  In these two images, I would expect the greenish 
crewman in the water to be in the exact same position.
ttbo1392 crewman is an absolute vector
ttbo1393 crewman is relative to tugboat.

The scenario is, crewman is drifting in the bathtub and gets rescued by 
the Tug.  So his vector starts out absolute and the moment the rescue 
starts, he becomes part of the tugboat object.

TugVec =<700.50, 144.50, 215.50> Rot=<4.04, 155.00, 1.73>
CrewVec=<697.50, 143.92, 217.00>

So, CrewOnBoatVec=vrotate(CrewVec-TugVec, y*-TugRot.y)

which gives me
CrewOnBoatVec=<2.08, 0.00, -2.63>
close, but no cigar.
Ignore the y component. That gets handled special. It's the x,z that's 
the issue.

If I unwind it,
vrotate(CrewOnBoatVec, y*TugRot.y)+TugVec
I get back the original absolute CrewVec, but that just verifies the 
math works, but it's still wrong.

I don't know what I'm doing wrong.
-- 
dik
Rendered 49,882,521,600 of 49,882,521,600 pixels (100%)


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ttbo1392.png

Preview of image 'ttbo1393.png'
ttbo1393.png


 

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