#different UCS
4 messages in this thread
Dietmar – That's a neat idea, but can't you do this right now? The UCS table
contains the information needed to find the Z-axis vector of the UCS, and the
(trans) function will accept that as well. I've never tried it, but it should
be possible, requiring a little matrix math.
-TonyT.
Tony,
well, you're quiet right, but …
The UCS table contains the X and Y directions but not the Z direction. OK,
you can calculate that, but I'm too lazy to do that. Always thought that
calculations are something for computers not for people <g>.
BTW I doubt that it will be easier/faster to scan the UCS table, calculate
the Z axis and put that into (trans) than to (trans) into WCS first, change
UCSes and (trans) back.
So I make this a wishlist item.
Dietmar
Dietmar:
> But I doubt that it would be easier/faster to scan the UCS table,
> Calculate the Z-axis, and put that into (trans), then to trans into
> the WCS first, change UCSes and (trans) back.
I don't understand, Dietmar, if you do this using the UCS command, then
what do you think AutoCAD does in order to determine the new UCS? It has
to go thru the same steps (look up the saved UCS, compute the normal or Z-
axis vector, and then compute the internal transformation matrix that it
uses to compute coordinates in the UCS).
If you want to make a wish for (trans) to accept the name of a saved UCS,
then it too, must lookup the UCS, compute the matrix, and do the transform,
but I don't know how much faster AutoCAD can do it, as opposed to an ADS
program (of course, LISP is just plain slow at this, which is one argument
for the feature).
I'm not opposed to it, I just think its easy enough to do right now, and I
thought I'd bring that to light.
-TonyT.
You're right, an ADS function ought to perform this task as fast as ACAD
does, or even faster <g>.
I was talking to LISP, so performance and ease-of-use are still a matter of
fact.
On the other hand I'm not so enthusiastic about ADS because of some reasons:
– There are still versions of ACAD that don't support ADS and they will for
some years.
– You can port AutoLISP code across platforms in a snap. This doesn't hold
for ADS code (at least you'll need another compiler and linker)
– There are gigabytes of tested and debugged LISP code. Why rewrite that?
– Performance is not a key issue in complex design tasks. E.g. an
application of mine (which I call typical) runs 2 minutes with user
interaction disabled. In the standard case with user interaction it runs
about 20 minutes since the user has to make some design decisions he has
to think about. So there's no need to reduce the program's running time to
1 minute and the total time to 19 minutes.
– Last point: I'll wait for ADS support of a high level language like LISP
instead of low level languages like C or FORTRAN.
Dietmar