hidden line removal...

I've got a 3d object, actually I've got all the points that make up a 3d
object. How would I go about removing the hidden lines, or rather in my
case, making them dashed?

TIA,

Devin

 

there are different ways to do it

the best way to do it depends on the complexity of your 3d model, what
version of autocad, ...

I assume you know about hide, hideprecision, hide plot, isolines, dispsilh,
facetres, obscured lines, halogap, solview...
here are a couple of TRANSPARENCY methods you may not know about:

1.
your 3d model contains whatever 3d objects that define the object, you also
want to define the hidden line representation of the model: On a separate
layer of your 3d model, say HIDDEN, simply draw lines over the edges that
you want to show dashed.
NOW, in a separate drawing, you'll set up a sheet with two viewports: In one
viewport include the layers that make up your 3d model, and exclude the
HIDDEN layer, set the viewport to hideplot. In the other viewport, include
ONLY the HIDDEN layer and you dont have to set the viewport to hide. The
view in both viewports should coincide exactly!
when you plot, the first viewport shows the 3d object hidden, the second
viewport overlays the hidden line representation.

2.
define a linetype thus:

*TRANSPARENT_HIDDEN,dashed line that does not hide behind 3d objects
A,.25,["",STANDARD],-.125

Now trace over the desired edges of your 3d model with lines having this
linetype. the lines should go on the same layer as the edges they coincide
with and have the same or lighter lineweight.
Hide operations will see the embedded text ("") in the linetype, and ignore
the entire line, allowing it to show through 3d objects! (as long as
HIDETEXT is off).

good luck,
matt

 

OBSCUREDLTYPE=2

 

I think that will work, thanks!