Global Topology Palette
You can make objects topologically the same by picking either
two points or two curves and selecting the Glue button. Surfaces
and vectors cannot be glued. If no objects are picked, all visible objects
are glued using the specified tolerance. When two objects are glued, the
respective objects are then considered to be topologically adjacent. For
example: If you glue two curves that are each connected to two different
surfaces, these two surfaces are now considered to be topologically adjacent.
CAUTION: If you pick two curves of significantly different lengths, there
may be serious problems generating a quality surface grid.
You can set the tolerance, which is the maximum distance which
entities can have between them to be considered the same entity, by using
the Tolerance field. If you are unsure of the value that would suit
your project best, you can glue a couple of entities separately (like two
curves or two points), and see what the maximum distance is between them;
it will be listed in the message field. If the distance is about the same
in each example checked, the tolerance can be set to a number just slightly
higher than this given distance.
You can unglue by picking any number of curves and surfaces
and selecting the Unglue button. A message will appear telling you
the number of curves and surfaces unglued. If an edge that is not shared
by a surface is unglued, the result will be that the endpoints of the curve
are unglued from adjacent curves. If the edge is shared by adjacent faces,
each adjacent face will be unglued at the specified edge. If a face is
picked, all of the edges of the face will be unglued from adjacent faces.
The curves created by ungluing one face from another will still appear
to be one curve (they will be drawn on top of each other).
Creates a trimmed surface(s) from the surface(s) selected.
A surface can be trimmed only when it has a set of parametric curves that
form topologically valid (non-intersecting) loops. See curves
for how to build parametric curves. If the surface has bounding parametric
curves and another topologically valid loop on the inner area, the center
of the surface will be trimmed out of the inner loop. If the surface only
has one topologically valid loop, the surface around the loop will be trimmed
from the surface. If a trimmed surface is picked and Delete is pushed,
the trimmed surface will return untrimmed. For more information on
trimming see the trimming tutorials.
Before creating any grids, the model must be topologically
valid. A 3-D geometry is topologically valid if and only if all curves
have exactly two surfaces topologically adjacent to them. The Check
topology button checks the model for topological validity. The check
picks all objects that are topologically invalid.
Force topology check toggle
With this toggle turned on, all edges are included in the topology check.
By default, edges that are attached to a surface with a transparent bc applied are not included in the topology check.
You can pick degenerate curves (entire curve is within the
same point tolerance) and degenerate surfaces (at least one computational
direction is entirely within the same point tolerance) by selecting the
You have the ability to change the display resolution of a
given curve or surface by using the Resolution button. The display
resolution determines the accuracy of projecting curves onto surfaces as
well as curve-curve, curve-surface and surface-surface intersections. To
change the display resolution of a curve, put the desired resolution in
the U field and hit the Resolution button. To change the
display resolution of a surface change both the U and V fields
and hit the Resolution button. NOTE: U and V represent
the computational parametric directions of the given curve or surface.
For help in this area, please see the Topology
You have the ability to calculate the display resolution of
a curve or surface by highlighting the Calculate resolution toggle.
The resolution is calculated by multiplying the number of control points
by the order of the curve. CAUTION: Calculating the resolution of a curve
may produce thousands of segments and should be used sparingly.