extruding a 3d polyline and spline combo and turning them into a solid

extruding a 3d polyline and spline combo and turning them into a solid

office6PUWT
Advocate Advocate
3,853 Views
11 Replies
Message 1 of 12

extruding a 3d polyline and spline combo and turning them into a solid

office6PUWT
Advocate
Advocate

Re the attached .dwg file I'm not sure if a spline and polyline can be combined into a single polyline that can then be extruded and turned into a soild. can anyone please show me how to turn this sketch into  120mm wide arched beam?

0 Likes
Accepted solutions (2)
3,854 Views
11 Replies
Replies (11)
Message 2 of 12

Alfred.NESWADBA
Consultant
Consultant

Hi,

 

>> I'm not sure if a spline and polyline can be combined into a single polyline

Not to a polyline with just one command, but you can use command _JOIN to create a new Spline-object from your existing Spline+Polyline (a bit difficult with your geometry when you then try to close the open curve).

 

Alternative:

You can also try with command _SPLINEDIT to convert your Spline to a polyline, then run command _JOIN to join these 2 entities, make it closed an then extrude it. As shown here:

 

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
0 Likes
Message 3 of 12

leeminardi
Mentor
Mentor
  1. Close the gap where the 3D polyline meets the spline.
    image.png
  2. Give the region command and select the 3dpolyline and the spline.
  3. Extrude the region to create a 3D solid.

image.png

lee.minardi
Message 4 of 12

office6PUWT
Advocate
Advocate

Thanks guys, really helpful.

I decided to rework the original spline and repeated the operation but was unable to create a region from my new 3d polyline using the same approach. I've checked for any gaps in the closed geometry and cannot see any. I'd be grateful if you could take a look at the this file aswell and help define what the problem is this time?

0 Likes
Message 5 of 12

Alfred.NESWADBA
Consultant
Consultant

Hi,

 

you can use command _BOUNDARY to create a standard Polyline based on your 3D-Polyline, this new Polyline can be extruded.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
0 Likes
Message 6 of 12

office6PUWT
Advocate
Advocate

This has been a real headache, Boundary command worked for me but I had to redraw the geometry for a third time and now neither of the approaches you've shown me are working?? Could you have another look at it for me please. Attached saved as a 3d polyline from which I am unable to create a region or find any gaps.

all best

Luke

0 Likes
Message 7 of 12

Kent1Cooper
Consultant
Consultant

Does it need to be flat to make a Region?  Looking straight down the X axis which is at the right end [rotated for viewing orientation here]:

Kent1Cooper_0-1614626228761.png

Or, in plan view:

Kent1Cooper_0-1614626396484.png

 

Kent Cooper, AIA
0 Likes
Message 8 of 12

Alfred.NESWADBA
Consultant
Consultant
Accepted solution

Hi,

 

this time you have not drawn the objects in one plane, but to extrude a closed curve this curve has to be on one plane to get a 3D-Solid as result.

 

In this case you can help by setting the UCS to the plane you want to have the geometry projected to, then run command _FLATTEN and this should give you a geometry ready for running _EXTRUDE or _PRESSPULL.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
0 Likes
Message 9 of 12

office6PUWT
Advocate
Advocate

thankyou so much excellent advice.

0 Likes
Message 10 of 12

office6PUWT
Advocate
Advocate

I spoke too soon, after closer inspection the flatten tool has altered the axis of the object despite the ucs being positioned as required? see attached image

0 Likes
Message 11 of 12

Alfred.NESWADBA
Consultant
Consultant
Accepted solution

Hi,

 

First set the UCS to 3 of the endpoints of your contour.

Then use command _PLAN to this UCS.

Now run command _FLATTEN.

 

In worst case you need then to move the resulting geometry to the correct basepoint you'd like.

 

- alfred -

------------------------------------------------------------------------------------
Alfred NESWADBA
ISH-Solutions GmbH / Ingenieur Studio HOLLAUS
www.ish-solutions.at ... blog.ish-solutions.at ... LinkedIn ... CDay 2026
------------------------------------------------------------------------------------

(not an Autodesk consultant)
0 Likes
Message 12 of 12

office6PUWT
Advocate
Advocate

excellent thankyou

0 Likes