A major limitation of NURBS based surface design is
that if the designer wants to introduce additional control
in one region of a surface he must add complete new
rows and/or columns of control points. This proliferation
of vertices makes it difficult to produce a fair surface.
Autoship 9 introduces a system of introducing
local shape control on a surface without dealing with
unwanted control points.
A Feature Patch has default or user-defined boundaries.
It can be shaped by one or more control points. The
patch blends at its edges to the shape of the parent
surface. The blend transition may be positional, tangent
or curvature continuous.
When a surface has a patch applied, it is still fully
editable using only the original control points. When
the parent surface shape is changed the patch moves
with the change, retaining its own shape.
Patches may overlap and be nested.
A bow bulb
created as a feature patch. The patch area is indicated
by change in the mesh colour. The patch control points
used to shape the bulb are indicated, while the control
points of the base surface are hidden.
Ship hulls and superstructures are often designed as
several surfaces which must be joined at their edges
without leaving gaps. The Edge Mate facility allows
all or part of the edge of one surface to be matched
exactly to all or part of another surface's edge with
full control over the shape of the transition. The user
can choose positional, tangent or curvature continuity
from one surface to the other. The portion of the surface
used to make the transition is user-controlled. When
only part of an edge is mated, there is full user control
over the transition area at the end of the mate. Any
or all of the edges of a surface can be mated.
Project Integration and Export
Surfaces which incorporate Feature Patches and/or Edge
Mates are fully integrated into their Autoship
project. They are contoured, intersected, trimmed, meshed
and rendered just as any other surface. They also export
exactly via IGES, making transfer of designs from Autoship
to other programs simple and accurate.
In addition to these major tool additions, Autoship
9 incorporates other significant advances:
- A revised Navigator for organizing and accessing
model components. Points curves and surfaces can be
organized into collection trees for fast access.
- Edit planes. Define a plane oblique to the coordinate
axes and edit with respect to that plane. Edit in
the 3D view with respect to one of the principal planes
or an oblique plane which you define.
- Alternate main screen layouts.
- Surface colour. Make it easy to pick out one surface
in a complex design by assigning it a colour. This
is for outline drawing, not for rendering where Autoship's
system of surface finishes still applies.
- Translucency in rendering.
- Single button operation to create station contours
from baseline data.
- Increased use of context menus to speed access