Re: CAD to XYZ points

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Peter Mack" <peterbmack@...>
wrote:

>
> I am trying to find a way of outputting a text file of coordinates of
> points along the geometry of my CAD model. I have found a routine that
> will extract a list of all the points along splines, and any other
> points. What I want though is a way to produce a file of coordinates
> representing points at a given spacing along all geometry.
>
> ie if I have a 5 x 5 square drawn I want to be able to get a list of
> 20 points lying at the corners, and also at an interval of 1 along the
> lines. Same for circles arcs etc.
>
> I use 3D and 2d cad packages, so it would be nice to find a way to
> create a "point cloud" over a 3D surface too.

There are drawing routines(depending on your cad programs) to create
points at regular intervals on a surface. You can also define a grid
of vertical lines that intersect your surface and create points at the
surface-line(curve) intersections.

As far as creating points at regular intervals along an existing line,
arc or curve, divide the entity into the number of segments that you
want to create points and draw a point at the end of each resulting
entity. You can also interpolate a curve or arc into controlled short
line segments to create the same effect, but with points spaced
adequately to accurately reflect the curvature of the arc or curve (
more points is short tight curves as opposed to gently curving blends
with large radii).

Another technique is to draw a grid of lines ( like graph paper) and
calculate intersection points between the grid and the curves that you
are interested in. Use layers/colors, etc to keep your construction
geometry seperated( and seperable ) from the original and resulting
points.

Fred Smith - IMService
http://www.imsrv.com