POV-Ray : Newsgroups : povray.advanced-users : Cross products in different coordinate systems. Server Time
20 Oct 2025 13:15:43 EDT (-0400)
  Cross products in different coordinate systems. (Message 1 to 2 of 2)  
From: Bald Eagle
Subject: Cross products in different coordinate systems.
Date: 18 Oct 2025 19:35:00
Message: <web.68f423c95edf66ec1f9dae3025979125@news.povray.org>
Let's suppose that I have code that uses vector cross products in a z-up
y-forward system.

Now I want replicate the code in our y-up, z-forward system to accomplish the
same task.

            What is the best / most efficient way to do this?

Do I need to re-order the vectors in the vcross (A, B) function?

or

do I actually need to change the vector coordinates that I'm using
so that z-up <X, Y, Z> = y-up <X, Z, -Y>

I want something sane, for production code.  Not something hacktastic.

- BE


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From: jr
Subject: Re: Cross products in different coordinate systems.
Date: 19 Oct 2025 13:15:00
Message: <web.68f51c3e4edf73786ddd22546cde94f1@news.povray.org>
hi,

"Bald Eagle" <cre### [at] netscapenet> wrote:
> Let's suppose that I have code that uses vector cross products in a z-up
> y-forward system.
>
> Now I want replicate the code in our y-up, z-forward system to accomplish the
> same task.
>
>             What is the best / most efficient way to do this?
>
> Do I need to re-order the vectors in the vcross (A, B) function?
>
> or
>
> do I actually need to change the vector coordinates that I'm using
> so that z-up <X, Y, Z> = y-up <X, Z, -Y>
>
> I want something sane, ...

the latter (imo), re-order the components.


regards, jr.


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