Jump to content

Extrude along path - useless?

Recommended Posts

For the first time I thought I'd need to extrude along path, to get a handrail tube on top of posts that follow a bezier curve in plan and are all on different z-levels.

Well, I can't figure out what sort of objects I can use for this famous feature - everything I try fails because of invalid objects.

Can someone please explain the limitations of the feature?

Link to comment

Path objects can be any linear type object. This includes lines, arcs, circles, polygons, polylines, and nurbs curves.

Profile objects can be any of these except a nurbs curve. (Actualy a nurbs curve can be used as a Profile as well, but it must be flat on the plane.)

The most commong thing that causes a extrude along path to fail is a repeated point along the path, or points along the path in very rapid sucesion.

Link to comment

If your path has sharp bends in relation to the cross-sectional dimensions of your profile, the algorithm will not be able to process the calculation because the profile "turns in" on itself while going through your bend. Try using a small diameter circle, or change your path to have gentler curves, to test this answer.

This phenomenon is related to using the "Offset" tool with a complicated polyline. You can get an odd result that "crosses over" itself. AutoCAD, by the way, has programmed around this problem with their offset tool - you always get an offset polyline that has eliminated the cross-overs. Something for NNA to consider - unless the new versions have fixed this!

[ 10-02-2002, 03:34 PM: Message edited by: P Retondo ]

Link to comment

The required path was a 3D poly with six vertices - total length about 10 metres.No close or repeated points, no sharp bends.

The profile was a 50mm circle.

Tried even with a 3D poly with all vertices in the same y coordinates (to make it definitely 'planar.') Tried first converting to a NURBS. Tried a rectangle as the profile.

Nothing worked.

Link to comment
  • 2 years later...

I am not sure if this is off topic but I am trying to extrude along a path a profile moulding that I have imported as a bitmap and then used the trace bitmap command. Vectorworks keeps telling me that I have illegal objects in my selection (A trifle harsh I thought.) Can anybody help me with this as the abilty to inport standard mouldings that I use in my work is a great boon to me

Many Thanks

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...