converting star coordinates to x,y,z

[rick]

I hope you don't find this misplaced; pardon me, please, if you do.

I'm working on a project of modeling the stars of the constellations in
3-D; not for their positions relative to Earth, but relative to any
given person being at 0,0,0.

Is there a simple formula for this? ...or better yet, do you know
anyone who has them on the net or in a book?

Thanks!

Rick.

[rick]

Clarification:
I see that I too hastily posted the question. 0,0,0 would be Earth.
The
figure for 'x' would need to be the distance from Earth, with y and z
being
taken from RA and DEC...is that right?

If we use the stars of Orions belt as an example, can you help me put
them
to x,y,z?

Alnitak: 400ly, RA 05 40 45.5, DEC -01 56 34
Alnilam: 1340ly, RA 05 36 12.7, DEC -01 12 07
Mintaka: 600ly, RA 05 32 00.3, DEC -00 17 57