UCS and points?

if the ucs is rotated then some of my lisp routines will not work corectly.........especailly the ones in which an objects insertion point is needed. For example if I select a block and want to get the insertion point I would use
(cdr (assoc 10 (entget (car (entsel))))). The point that is retrieved from this is different from where the block is located. Is there a way to retrieve from the actual location of the block relative to the ucs. In this particular drawing the ucs is rotated at 45 degrees and I have a block that is located at point (20 10 0) but the association code has (10 7.07107
21.2132 0.0)

 

Use trans to translate from UCS to WCS.

 

Or look into Help, type "points" into the Index, and see "converting between
UCS and WCS". Might provide some helpful information.

Kent Cooper, AIA


...

 

Or look into Help, type "points" into the Index, and see "converting
between

Since he's asking about modifying lisp functions to work in varying
coordinate systems, I assumed he'd want a lisp solution rather than a
command-line CAL solution, or the inelegant approach of calling CAL from
lisp

To translate from UCS to WCS: (trans <point> 1 0)

To translate from WCS to UCS: (trans <point> 0 1).

 

Whoops... When you get to that help page by way of the Index, it's not
obvious that it's a CAL subcommand.

But I think there's some OTHER way of converting on the fly, back in the
dark recesses of my memory, like putting some punctuation character before
the point coordinates or something. I think the main idea was that when
you're in a User Coordinate System, you can specify a point in the World
Coordinate System location without changing to the WCS to do it. Since I
haven't found it, I'm not sure whether it would work in a lisp routine or
not. Anybody remember what that is?

Kent Cooper, AIA

...

 

Kent,
The coordinate prefix for WCS is *.

The trans function as Tom has explained is what is
needed though.

Regards,
Doug

 

The coordinate prefix for WCS is *.

Gosh, I don't think I ever knew that!

The tricky part, to me, is keeping track of which things are kept in which
coordinate system. Best I recall, in different situations I've used
different strategies. Sometimes, I've translated every piece of info to WCS,
done any necessary calcs, then translated the result back to UCS. Other
times it's seemed easier to just switch to the WCS, do everything, then
restore the UCS after I'm done.