Trim and untrim surfaces
to meet the edges of other objects.
An
important step in the surface modeling workflow is trimming surfaces. You
can trim a surface where it meets an intersecting object or you
can project geometry onto a surface as a trimming edge.
When a surface is trimmed,
the removed surface areas can be replaced with SURFUNTRIM.
NoteSURFUNTRIM does not
restore areas removed by the SURFAUTOTRIM system variable and PROJECTGEOMETRY.
It only restores areas trimmed with SURFTRIM.
The Properties palette
indicates if the surface contains any trimmed edges.
Projecting Geometry onto
Surfaces, Solids, and Regions
Similar
to projecting a movie onto a screen, you can project geometry onto 3D
solids, surfaces, and regions from different directions to create
trimming edges. The PROJECTGEOMETRY command creates
a duplicate curve on the object that you can move and edit. You
can also trim against 2D curves that do not actually touch the surface,
but that appear to intersect the object in the current view.
Use the SURFACEAUTOTRIM system variable
to automatically trim a surface when you project geometry onto it.
Options for Projecting
Geometry
Project geometry
from 3 different angles: the Z axis of the current UCS, the current
view, or a path between two points.
Project to UCS -
Projects the geometry along the positive or negative Z axis of the
current UCS.
Project to View -
Projects the geometry based on the current view.
Project to Two Points -
Projects the geometry along a path between two points.
Procedure
To trim a surface
Click Surface
tabCreate
panelTrim.At the Command prompt,
enter surftrim.
Select the surface
and press Enter.
Select the cutting
curves and press Enter.
Select the surface
areas to remove and press Enter.
The selected areas are
removed.
To untrim a surface
Click Surface
tabCreate
panelUntrim.At the Command prompt, enter surfuntrim.
Select a visible part
of the surface and press Enter.
The trimmed areas are
replaced.
NoteWhen you trim a surface
multiple times, you may lose some of the original trimming edges.
In this case, some untrim actions may not be possible if the trimming
edge has been lost.
To automatically trim areas
to projected curves
Click Surface
tabProject
Geometry panelAuto
Trim.At the Command prompt,
enter surfautotrim.
Click Surface
tabProject
Geometry panelProject
to View.At the Command prompt,
enter projectgeometry.
Select the curve to
project onto the surface and press Enter.
