Weldments - Trim and Extend
You can use segments and other solid bodies to trim segments so they
butt up correctly in the weldment part. With Trim/Extend,
you can trim or extend:
Two segments
at a corner where they meet.
One or
more segments against another solid body.
Both ends
of a segment at once.
You should trim all corners in a weldment model to assure
that lengths of segments are calculated accurately.
To trim segments:
Click Trim/Extend
(Weldments toolbar) or Insert,
Weldments, Trim/Extend.
Set the
following options, then click
.
Corner Type
Click one of the following corner
types:
End
Trim 
End
Miter 
End
Butt1 
End
Butt2 
Bodies to be Trimmed
For End Miter, End
Butt1, and End Butt2 corner
types, select one body to be trimmed.
For End Trim corner type, select one or
more bodies to be trimmed.
Allow
extension. If the segment does not meet the trimming boundary,
lengthens the segment to its boundary.

Trimming Boundary
Select a trimming boundary type (for End
Trim corner type only):
Selecting Face
/ Plane as the Trimming
Boundary is normally more efficient and offers better performance.
Select Bodies only when trimming
against a non-planar entity such as a round pipe or a stepped surface.
Face/Bodies
For End Miter,
End Butt1, and End
Butt2 corner types, select an adjacent segment to trim against.
For End Trim
corner type, select one or more adjacent faces or bodies to trim against.
If you select Face / Plane for
Trimming Boundary, toggle keep or discard
to choose which segments to keep.

Preview. Select to preview the
trim in the graphics area. For performance reasons, disable this option
for complex structures until you have selected all the items to trim.
Allow extension. Select to allow
structural members to be extended or trimmed. Clear to allow only trimming.
When using this option, check the preview carefully to ensure that the
results are correct.
Simple cut between bodies
. Makes the structural members flush with the planar contact
faces (helpful for manufacturing).
Coped cut between bodies
. Trims the structural member to the contact body.
Weld gap. Select this option,
then enter the Weld trim gap
to allow space for
a weld bead. The gap reduces the length of the trimmed item, retaining
the overall length of the structure.
Callouts. If the trimming
boundary intersects the item to trim, callouts appear next to trimmed
segments with a body identifier and a toggle
for keeping or discarding the segment.
If you trim with a plane or a face and keep
all pieces, the pieces are cut. If you discard any of the pieces, the
remaining adjacent pieces are combined.