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AeroHydro,
Inc.
The most advanced 3D surface modeling available...
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MultiSurf tipsOver the years we have written down and collected a
large number of tips on the use of MultiSurf, which we want to share
with the users. The tips are organized in six categories. Modeling Techniques
Tips: Viewing/Displaying
Tips:Organizing/speeding up your model
Tips: Importing files into MultiSurf
Tips: Commands
Tips: Troubleshooting/Diagnosis
Straight portions on BCurves and CCurves All of these techniques involve arranging control points that lie accurately in a straight line. To create a series of points that lie durably on a straight line,
BCurves, type 2: To make a portion straight, put at least three consecutive control points on a line; the straight portion will start and end at midpoints between control points. See PWRB2.MS2. BCurves, type 3: Put four consecutive control points on a line; the straight portion will be (approximately) between the second and third points. CCurves: The key is to put two control points very close together at the end of the straight section -- for example a bead at t=0.0001 or t=0.9999. For an example, see sample file STRTPART.MS2. This method makes excellent chines and keels for powerboats.
When you know the center and a start point at the correct radius, use a type-3 Arc. When you know the axis and a start point at the correct radius, use a Helix with pitch=0 and angle=360 degrees.
Create a Frame from three points or a
Roll/Pitch/Yaw Frame from one point and use this as a "sketching plane".
Surface with a complex boundary If you are designing a surface with a complex boundary (more than four sides), first make a fair basis surface (using whichever kind of surface gives you the overall fair shape), then trim out the surface you want with a SubSurf or a TrimSurf. Use a SubSurf if the surface can be bounded by 2 snakes. A TrimSurf is best for all others Example applications: topside surface above a chine with steps; broken or stepped sheer.
Often the simplest way to make a flat rectangle is with a type-1 BSurf having only four
control points -- the four corners. If you know three of the corners, make the fourth
as a CopyPoint from the three known corners.
Suppose you have three points 'p1', 'ctr' and 'p2', and you need to construct geometry in the plane that bisects the angle 'p1'-'ctr'-'p2'. Make a type-2 Arc from 'p1', 'ctr' and 'p2'. Put an AbsBead 'mid' at the center of the arc (t=0.5). Then make a Frame 3 'frame' from 'ctr', 'mid' and 'p1'. The x,z plane of 'frame' is the plane that bisects the angle; the x,y plane is the plane of the original three points.
Making a copy of a surface in a new location If the copy is a mirror image of the original, use a MirrSurf. If the copy results from rotating the original about an axis, use a RotatSurf. If the copy is displaced parallel to the original, use a RelSurf with just one point (at the new location of the (0,0) corner). A CopySurf is much more versatile – the copy can have any position and location relative to the original, and can be nonuniformly scaled in the process.
Build the part in a Frame, using Point objects with the Frame as their parent. When you relocate or reorient the frame, anything built from these points will go with it. Example: FRAME1.MS2
To position a bead at a given distance along a curve from either end, or from another bead, make an ArcLenBead.
The offset can be positive or negative (forward or backwards along the curve). See ARCLENBD.MS2 in Examples folder.
Locating a bead at a particular X coordinate along a curve Use an XYZBead (type-1 to use X as the coordinate).
Wrapping an extrusion onto a surface Use a SweepSurf – "path" is a snake on the surface, "guide" is an OffsetCurv made from the snake, and "shape" is the cross-section. Examples: GUARD.MS2, GUARD1.MS2
Specifying slope at the end of a curve BCurves - Position the second control point in the desired direction from the end control point (a BCurve always ends tangent to its polyline). CCurves - You can put the second control point very close to the first, in the desired direction. The CCurve has to go through both points. XCurves - You can specify the end slopes as numerical values. If you want to specify the end slopes as angles, use a Point with Polar coordinates for the second control point.
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