[OpenSCAD] Dumb questions for you experts

Clifford Wolf clifford at clifford.at
Fri Jan 15 09:50:32 CET 2010


Hello,

On Thu, Jan 14, 2010 at 11:12:25PM +0000, gibell at comcast.net wrote:
> [...]  So it looks like I am out of luck as far
> as upgrading to OpenGL 2.0.  Have I no other options, other than
> finding or buying a different machine?
> Are there other advantages to using OpenGL 2.0, other than speed?  I
> don't see much on this issue in the manual.

unfortunately the manual does not cover the user interface atm..

when you have OpenGL 2.0 there is the "OpenCSG" [1] view mode where you can
view your model instantanously without building it using CGAL. without
OpenGL 2.0 there is only the "Thrown together" mode in which the CSG
operations (difference, intersection) are not performed but instead all
bodies are fully drawn.

With OpenGL 2.0 it becomes much easier to make complex designs because the
test cycles are much shorter.

> On an unrealated issue, I tried the "multmatrix" transformation and it
> doesn't appear to be working.  Is there an example of the use of this
> transformation?  Why a 4x4 matrix and not 3x3?
> Thanks in advance for any help anyone can give!!

as to why it is a 4x4 instead of a 3x3 matrix I'd like to refer you to any
better OpenGL introduction.

maybe you got the syntax for multmatrix() wrong. The following example
translates the child objects along the vector [10, 20, 30]:

	multmatrix([
		[1, 0, 0, 10],
		[0, 1, 0, 20],
		[0, 0, 1, 30],
		[0, 0, 0,  1]])

However: usually one does not need to use multmatrix() directly but use a
combination of the other transform statements translate(), scale() and
rotate() instead.

yours,
 - clifford

-- 
If Python is executable pseudocode, then perl is executable line noise.


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