[PythonCAD] Some problems... and ideas

Rafael Villar Burke pachi at mmn-arquitectos.com
Thu Dec 22 15:01:31 CET 2005

I'd appoint to some other ideas on top of Jose Antonio ones:

José Antonio Martín Prieto wrote:

> Hi,
> Trying to get familiar with PythonCAD, I've been drawing a simple ISO 
> sheet (just to draw something) and I have many problems to draft such 
> a simple drawing. I'm using autocad everyday, and the behavior of 
> PythonCAD is being hard for me. Some examples:
> - Is there any way to introduce relative coordinates? In autocad this 
> is done by typing a "@" before the coordinates.

Relative coordinates are really useful, and there's also a really 
rocking autotrack (polar tracking + object snap tracking) feature in 
AutoCAD that I use all the time:

 From the autocad help:
"""AutoTrack helps you draw objects at specific angles or in specific 
relationships to other objects. When you turn on AutoTrack, temporary 
alignment paths help you create objects at precise positions and 

"""Use polar tracking to track the cursor along temporary alignment 
paths defined by polar angles relative to a command's From or To points. 
[...] If you turn on the 45-degree polar angle increment, AutoCAD 
displays an alignment path and tooltip when your cursor crosses the 0 or 
45-degree angles. The alignment path and tooltip disappear when you move 
the cursor away from the angle.
You can use polar tracking to track along polar angle increments of 90-, 
60-, 45-, 30-, 22.5-, 18-, 15-, 10-, and 5-degrees, or you can specify 
other angles."""

"""Use object snap tracking to track along alignment paths that are 
based on object snap points. For example, you can select a point along a 
path based on an object endpoint or midpoint or an intersection between 
To use object snap tracking
1    Start a drawing command.  (You can also use object snap tracking 
with editing commands, such as COPY or MOVE.)
2    Move the cursor over an object snap point to temporarily acquire 
it. Do not click the point; pause over the point briefly to acquire it.
Acquired points display a small plus sign (+), and you can acquire more 
than one. After you acquire a point, horizontal, vertical, or polar 
alignment paths relative to the point are displayed as you move the 
cursor over their drawing paths."""

Once a polar direction is adquired you can enter a number, and a point 
in such direction, at the given distance is entered. This is extremely 
useful, really. With it you don't need ortho at all.

> - Is there any way to copy an object from a base point to another 
> point? If not, I think this could be easily implemented as a "move" 
> operation but without deleting the object being moved.
> - When I draw a segment just over another one, do the two segments 
> exist or are they merged? In the first case, how do I select only one 
> of them?

In AutoCAD this is solved using cyclic selection. When you press CTRL 
and later select an object that's over any other objects it gets 
"preselected" and is highlighted in dashed lines, if you keep 
left-clicking then the object that is preselected rotates through all 
the piled objects, until you press enter or right-click. After this 
point you have a new selected object... you could continue adding some 
more objects to the selection using any mode, add another one in the 
pile using again this mode...

To deselect objects you use SHIFT while selecting the object to be 

> Regards,
> Jose Antonio

I hope this brings in some new ideas,

Rafael Villar Burke

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