 | | How to make a squish matrix?
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Hey all, Is there a way I can make a matrix that will "squish" an object? For example, I have a cylinder I want to squish into a truntcated cone. I could have sworn this was possible (I thought this was how perspective was rendered, by squishing the (...) (23 years ago, 24-Apr-01, to lugnet.cad)
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| | Reiterate: How to make a squish matrix?
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(...) Whoops! Thank you Rui for helping me straighten this out -- I'm not doing this in LDraw. I'm just looking for a way to do this with a 4x4 matrix. My target app is POVRay, but I figured this question would be generic enough for people in the (...) (23 years ago, 24-Apr-01, to lugnet.cad, lugnet.cad.ray)
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| | Re: Reiterate: How to make a squish matrix?
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A quick keyword search turns up this page which states that it is NOT possible (in one of the first few paragraphs). (...) (23 years ago, 24-Apr-01, to lugnet.cad, lugnet.cad.ray)
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| | Re: Reiterate: How to make a squish matrix? [DAT]
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i thought you just had to multiply your matrix with something like 1 0 0 0 2 0 0 0 1 this would make Y 2 times as long. Not? Koen Don Heyse <dheyse@hotmail.spam....away.com> schreef in berichtnieuws GCBD52.3qI@lugnet.com... (...) (URL) (...) target (...) (23 years ago, 25-Apr-01, to lugnet.cad, lugnet.cad.ray)
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| | Re: Reiterate: How to make a squish matrix?
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(...) Yes, but it's not what Sproat needs. He needs to scale X and Z as a function of Y. Something like: x' = xy Which is something transform matrices cannot do. Steve (23 years ago, 25-Apr-01, to lugnet.cad, lugnet.cad.ray)
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| | Re: Reiterate: How to make a squish matrix?
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(...) Yah. Bummer. Thanks, though, to Dan and Steve. Cheers, - jsproat (23 years ago, 25-Apr-01, to lugnet.cad, lugnet.cad.ray)
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| | Re: Reiterate: How to make a squish matrix?
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that shouldn't be too hard either. just operate the matrix on the points alone. if your cilinder has it's axle around the Y axle. L is the length of the cilinder and if it starts at 0 0 0 you could use (1-y/L) 0 0 0 1 0 0 0 (1-y/L) this would turn (...) (23 years ago, 25-Apr-01, to lugnet.cad, lugnet.cad.ray)
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| | Re: Reiterate: How to make a squish matrix?
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(...) Yes, but you cannot put (1-y/L) into a transformation matrix. It is a *function* that changes for each 3D point. The purpose of a tranformation matrix is to precalculate a matrix of *numbers* that gets multiplied by all the points of the (...) (23 years ago, 25-Apr-01, to lugnet.cad, lugnet.cad.ray)
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