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 CAD / Development / 9030
9029  |  9031
Subject: 
Re: Mirrored parts and studs
Newsgroups: 
lugnet.cad.dev
Date: 
Wed, 2 Jul 2003 18:12:02 GMT
Viewed: 
1713 times
  
In lugnet.cad.dev, Travis Cobbs wrote:
In lugnet.cad.dev, Don Heyse wrote:
In lugnet.cad.dev, Jacob Sparre Andersen wrote:
Anyway.  Since we are only talking about studs, the rendering programs
_could_ simply remember to fix any mirrored studs (can be done by
multiplying the rotation matrix of the object with the sign of its
determinant).

Umm, my math is really rusty.  Can the sign of the determinant also
be used to detect mirroring?  That could be handy.

Yes.  That's what LDView does.

Yeah, I did a search for determinant and found your note.  I tried
the on-the-fly fix in ldglite with the L3 structs and it seems to work,
although I'm not sure I'm applying the fix correctly.  Is it really
as simple as multiplying some matrix by -1?  I must have been applying
the -1 to the wrong matrix, so I went with mirror around the Z axis
transform instead.  Can you point me to the ldview code that does this?
I'm feeling rather lazy today, asking for help before looking for
myself...

Thanks,

Don



Message has 1 Reply:
  Re: Mirrored parts and studs
 
(...) I don't actually do any transformations in LDView to get the logos right. I just detect the mirroring (by tracking negative determinants and flipping the mirrored bit every time I see one) and modify my texture coordinates to un-mirror (...) (21 years ago, 2-Jul-03, to lugnet.cad.dev)

Message is in Reply To:
  Re: Mirrored parts and studs
 
(...) Yes. That's what LDView does. --Travis Cobbs (21 years ago, 2-Jul-03, to lugnet.cad.dev)

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