MultiSurf 6.5 Reference: What s New

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1 MultiSurf 6.5 Reference: What s New MULTISURF 6.5 REFERENCE: WHAT S NEW...1 What s New in MultiSurf Customizable Manager Dialogs... 3 Snake Trim Tool... 4 New Trimmed Surface... 5 Tools/Velocity Profile... 5 Tools/Graph Profile... 6 Tools/Tangency Profile... 7 Tools/ Clearance Profile... 8 New Menu Items... 9 File/Export3D/PAT Meshes... 9 Edit/Model File... 9 Tools/Trim Snake... 9 View/Display/... 9 View/Managers... 9 New Functions... 9 Edit Model File Area Select in Parent picking mode New Default Point Color Formulas for Contours New Radius Arc type Double Click Select from "Which Entity" dialog Contours can now be placed on Surface edges Command-line script operation Command scripts Script execution... 11

2 P.O. Box 684 / 54 Herrick Rd. Southwest Harbor, Maine U.S.A. voice fax support@aerohydro.com website

3 2006 AeroHydro, Inc. What s New in MultiSurf 6.5 The "new" functionality added to the release of MultiSurf 6.5 are the following: Customizable Manager Dialogs Snake Trim Tool New Trimmed Surface Entity Tools/Velocity Profile Tools/Graph Profile Tools/Tangency Profile New Menu Items New Functions Edit Model File Area Select in Parent picking mode Default point color is yellow Formulas now available to define Contours New Radius Arc type Double Click Select from "Which Entity" dialog Contours can now be placed on Surface edges Command-line script operation Customizable Manager Dialogs MultiSurf has been optimized for dual screen viewing. When the program is initially opened the 4 Manager views are arranged from left to right in the wireframe window. These panes are now independent, dockable, and able to be dragged to a second monitor. In the image below the Entity Manager and the Selection Set are arranged across the top. The wide view for the Selection Set gives the user the full benefit of all the information contained. Previously this information was hidden to save space for the wireframe window. This arrangement could be seen as an improvement on previous versions or an optimal arrangement for one monitor. The Entity Manager is docked next to the Selection Set. It is not as long as one would like in this configuration, but is quite manageable for smaller models. A space for this manager on a second monitor would be best. The Property Manager is left to float on the screen. This way the full length of the pane can be viewed. The pane could be docked but that would cut in to available wireframe viewing area. If it is desirable to see a full unobstructed wireframe window, the Property Manager could be temporarily closed and would need to be opened from the View Menu or by using the appropriate icon in the Manager View bundle.

4 The Available Entities Manager is not open in this sample arrangement. We still suggest it remain closed with larger models, to improve performance. At least space is not an issue now, if two monitors are employed. Entity Manager Selection Set Property Manager Snake Trim Tool Shortcut: <T> on the keyboard or: An automatic snake trimming operation has been added. Select 2 snakes which cross. The first snake selected will be the Trim Tool and the second the Snake to Trim. Press <T> on the keyboard and the cursor will change to a Scissors. Hover over the snake to trim and you will see a color change wherever you hover. Click the mouse to Trim the highlighted end of the snake. If you need to trim the other snake, simply control click the other snake, press <T> and you repeat the process. At this time the basis snake and supporting points for the SubSnake are hidden and kept on the current layer.

5 New Trimmed Surface Trimmed Surfaces no longer need to have snakes, which lie on the surface boundary, to be included in the Trimming Loop. Existing Trimmed Surfaces will remain and be labeled (Obsolete) in the Property Manager. Every new Trimmed Surface will be of the new variety. The primary difference is the requirement of a magnet to name the Surface to be Trimmed and also to serve as a locator of what part of the surface is to remain after trimming. Tools/Velocity Profile [Available when one curve or snake is selected.] The velocity of a curve is the rate of change of distance (arc length) along the curve with respect to change in the t parameter. For example, on an unrelabeled Line or Arc the velocity is constant equal t-intervals have exactly equal arc lengths. But on a BCurve the velocity depends on the spacing between control points, being low in regions where two or more control points are close together and relatively high where control points are far apart. On most kinds of curves, velocity is variable with respect to t -- the product of the particular mathematical operations involved in computing the curve. A discontinuity (jump) in velocity, as can occur especially with PolyCurves and PolySnakes, is generally quite unapparent in a wireframe view, but it s just as much of a challenge for curve fitting as a discontinuity in slope. The chief advantage of a PolyCurve2 (or PolySnake2) is that the velocity is automatically balanced at each junction, removing any velocity discontinuities. This makes it much easier to approximate with B-spline (NURBS) math. A curve can have zero velocity due to either relabeling or, for some curve types, to the locations of control points. For example, a Relabel that starts with two zero values, e.g. {0, 0, 1} produce zero velocity at the t=0 end of any curve. {0, 0, 1, 1} produces zero velocity at both ends. For another example, a BCurve that uses the same point twice at either end will have zero velocity at that end. This can happen if you accidentally select the same control point twice, an error which may not be at all apparent in the shape of the curve. Zero velocity on a curve can cause trouble in constructions based on that curve for example, a TanPoint won t evaluate if its bead is at a zero velocity point; a SweepSurf can t have a zero velocity point on its path curve. A curve that has zero velocity at either end may have no fair extension beyond that end. Turning on tickmarks (visibility option 2) is one way to visualize the velocity distribution of a curve. Velocity is low where the tickmarks are close together, high where they are far apart. Tools/Velocity Profile is a much sharper tool for visualizing velocity. It displays a graph of the velocity distribution, similar in appearance to the Curvature Profile. The differences are: 1 the ordinate plotted is the velocity rather than the curvature 2 the horizontal axis of the graph is just the t parameter. Tickmarks at 0.1 intervals (in the t parameter) assist in the t locations of graph features.

6 The Porcupine button and command work with Velocity Profile as well as Curvature profile. This provides an alternative presentation of velocity variation, displayed as a set of short lines or quills perpendicular to the displayed curve, each with length proportional to the local velocity. Example: Open sample file POLYCRV1.MS2. Select the PolyCurve midsection and activate Tools/Velocity Profile. The graph indicates that each of the 3 segments between junctions has constant velocity. However, the three velocities are different, so there are discontinuities (shown as steep jumps) at the transition t values of 0.4 and 0.6. Click the Porcupine button; this turns on the Porcupine display, which provides an alternative visual indication of discontinuities in velocity at t = and Select the three component curves bottom, bilge, and side in that order, and create a PolyCurve2. Display its velocity profile; it will be 100% constant. The applications of Velocity Profile are chiefly diagnostic. Why is this SweepSurf complaining about the curve I ve given it for its path? Why does this curve or snake approximate poorly during IGES export? it looks smooth enough. Why are the longitudinals on my CLoft hull compressed in this region? Often the Velocity Profile will provide the answer to these questions. Tools/Graph Profile [Available when one Graph or Relabel object is selected] This new Tools option provides a graphical interface for viewing Graph and Relabel objects. A Graph object is a real-valued function of a single parameter (usually designated t, like the t parameter on curves and snakes). Graphs are used to greatly enrich the possible geometries created by several entities, for example RelCurve, OffsetCurv, BlendSurf and SweepSurf. Relabels are a special type of graph used to control the t parameter distribution on curves and snakes. Graphs and Relabels are non-graphic entities that can t be seen directly in a wireframe or rendered view (although they usually do have visible effects on the objects they support). Note that as non-graphic objects, Graphs and Relabels can t be selected directly in the wireframe view. If you know their names, you can select them from Selection Set view (<F6>), or with Select/By Name. Alternatively, select a graphic object that uses the Graph or Relabel as a support, and edit its Graph or Relabel attribute; then open the Graph Profile. Tools/Graph Profile opens a window similar to the Curvature or Velocity Profile windows, showing a plot of the graph over the parameter range 0 to 1, and the location of its control values.

7 This example is the graph used as a blending function in the sample file RELCURV1.MS2. It is used in the model to control the width of the spray flat on a planing hull bottom. It is a type-3 BGraph with 8 control values: 0, 0.25, 0.65, 0.85, 1.0, 1.0, 1.0, 1.0 Tools/Graph Profile -- Interactive (key-drag) editing Tools/ Graph Profile has provided a way to visually relate to graphs and relabels. In MultiSurf 6.1, this feature has been enriched to allow interactive editing of BGraph and Relabel controlpoint values. To activate this, select a BGraph or Relabel object and invoke Tools/ Graph Profile. The graph is displayed, as usual. You can click on any control point (the small circles), which gets marked with a red diamond, indicating it is the "active" control point. Then you can take these actions: (1) Holding down the <Ctrl> key, use the up or down cursor (arrow) keys to nudge the control point up or down, in coarse increments of (2) Holding down <Ctrl> and <Shift> keys, use the up or down cursor (arrow) keys to nudge the control point u or down, in fine increments of (3) Holding down the <Ctrl> key, use the right or left cursor (arrow) keys to move to the next or previous control point. As you modify the graph control points, the model and any open views will dynamically update to reflect the changes. Key dragging terminates when you release the <Ctrl> key, or move the focus to another window; then the red diamond disappears. Tools/Tangency Profile Design problems often arise where it is desired to make one surface approximately or exactly tangent to another surface. This can occur with two surfaces joining edge-to-edge, or where one surface edge is constructed as a snake on another surface. It is generally difficult to tell in either wireframe or render view how accurately this tangency has been achieved. One way that has been available to make a quantitative measure of tangency is the following construction. Suppose the edge of surface 'B' is intended to be tangent to surface 'A' along some snake 'N' that lies in surface A. Make an AbsRing 'r1' somewhere on 'N', and an OffsetPt 'opa' from 'r1', with an offset.of 1 unit. Make a ProjMagnet 'pm' from 'r1' projected onto 'B', normal to 'B'. (The distance of projection will be essentially zero). Make a second OffsetPt 'opb', 1 unit from 'pm'. Then you can use Tools/Angle with 'opa', 'r1' and 'opb' selected, to measure the difference in direction of the normal vectors to the two surfaces. You can move 'r1' to different places along 'N', and repeate the Angle command, to see how the angle varies. Tools/Tangency Profile essentially automates this construction at many points along the junction, and displays the result as a graph, similar to Curvature Profile. Tools/ Tangency Profile

8 is enabled on the menu when one snake and one surface are selected. If you don't already have a snake along the junction, an EdgeSnake is the obvious choice. In this example, the tangency is being measured along an EdgeSnake 'n0'. The angle is accurately zero at both ends of 'n0'. Along the length of the snake, the angle varies from slight positive values (less than 0.1 degree) near t = 0.10, to approximately -1.4 degrees near t = Tools/ Clearance Profile In complex designs there are often needs to make two curves or surface edges that are as close as possible to identical, or a curve that lies on a plane or surface as accurately as possible. MultiSurf provides many constructions that allow such joins to be made exactly, often by means of various kinds of snakes. But sometimes it is necessary to approximate these joins; for example if your design is restricted to NURBS surfaces, which usually can't make exact joins, or must be communicated through an IGES file, which cannot represent the exact junctions. One way to check the distance between a curve A and another curve B is to put an AbsBead 'e1' on A, at some arbitrary parameter value, and a ProxBead 'e2' on B, at minimum distance from 'e1'. Then with Tools/Distance or Tools/Clearance you can read the distance between the two beads (which would be zero if the junction were exact. Moving 'e1' to various positions along A and repeating Tools/ Clearance would eventually let you assess how the clearance is distributed. If the question is clearance between a curve and a surface, you could do the same thing with a ProxMagnet on the surface; if it's clearance between a curve and a surface edge, you can put an EdgeSnake on the surface and use a ProxRing. Tools/ Clearance Profile automates this procedure and displays the results as a graph, similar to Curvature Profile and Tangency Profile. Clearance profile is enabled when there are two objects selected, the first being a curve (including a line or a snake) and the second being a curve, surface, or plane. The quantity displayed is a distance (units of length), vs. the parameter value t on the curve. Clearance from a plane or surface is a signed quantity, positive in the direction of the positive normal. Clearance from a curve is always positive or zero. In this example, the selection set consists of EdgeSnake n3 on one surface, and the matching EdgeSnake on an adjoining surface. The clearance is zero at the two ends, and at two other places

9 along n3 -- approximately 0.28 and 0.85, as indicated by the tickmarks. This model is dimensioned in meters, so the maximum discrepancy is approximately 0.35 mm, at about t = New Menu Items File/Export3D/PAT Meshes Exports a.pat file from a selection Set of from the visible surfaces. Edit/Model File See below. Tools/Trim Snake See "Snake Trim Tool" above. View/Display/. Velocity Profile Graph Profile Relabel Profile Tangency Profile Clearance Profile View/Managers From this menu selection the user is able to toggle the visibility of the Available Entities, Entity Manager, Property Manager, and Selection Set panes. New Functions SIGN, FLOOR, CEIL, PI, ALARM, ROUND2 have been added since the MultiSurf 6 release and are not yet in any documentation. SIGN(x) is +1 when x > 0, -1 when x < 0, 0 when x = 0 FLOOR(x) is the greatest integer that is less than or equal to x CEIL(x) is the smallest integer that is greater than or equal to x PI has 1 argument, but its value is immaterial; PI(x) = pi for any x. ALARM has 2 arguments ALARM(x,y). The alarm "goes off" (goes into error) if (1) it is set (x > 0) AND (2) y < 0. Using a formula or expression for y, you can build various warning limits into a model. ROUND2( x, places) rounds x to the specified number of decimal places. E.g., ROUND2(PI(0),2) is

10 Edit Model File Area Select in Parent picking mode In MultiSurf 5.0 this functionality was present but was not ported over to the new interface. It was soon discovered by our users and brought to our attention. This is particularly useful when Inserting Contours. Enter the "Surfaces to Cut" picking mode and area select the visible surfaces and they will be added to the Parent Selection Set. New Default Point Color The new default point color has been changed from black to yellow. This is much better suited for users who like to use a black background color. Formulas for Contours New Radius Arc type A fourth Radius Arc type has been added. The arc starts tangent to a line between points 1 and 2 and ends where it crosses a line between points 2 and 3. The parents would be the 3 points and a radius value. This would be a great entity for a constant radius deck (RadArc4.ms2 in the Examples folder) or you could insert a formula for the radius and make a constant percent camber deck. The arc could also be used for the basis curve of a cylindrical transom. Double Click Select from "Which Entity" dialog A recent customer request which was implemented. Contours can now be placed on Surface edges

11 A customer recently brought to our attention he was not able to place a contour on a surface edge. An example being where the surface starts at X=0 and that would be the location of the desired first contour. We are pleased to report this is now possible. Command-line script operation MultiSurf 6.5 has a new option to run a script of commands from the MS-DOS command line. This allows MultiSurf to function as a geometry server in a system of programs, for example for automated design, analysis, and optimization. Command scripts The script syntax used is identical to the syntax for commands in Tolls/ Command Window. To see a list of the available commands, open the Command Window and give the command: Help To see the syntax for an individual command, use "Help command-keyword"; for example: Help ExpandLists A command script is stored as text file of commands. Notepad is a convenient application for preparing and editing text files. Example. This file, named cmd.txt, and located in c:\temp, is a valid command script: SetPath c:\ File.Open demo.ms2 SetFloat P File.Export3D.3DA File.Close This sets the working directory to c:\ (the root directory of drive c:); opens a copy of demo.ms2 (that must exist in this folder); modifies the geometry by moving a control point; exports a 3DA file (using the default name, Demo.3DA); and closes the model file. Script execution First, if MultiSurf is already running, close the program. (It can't start a second instance when one is already running.) Open an MS-DOS command window, and navigate to where your MultiSurf executable lives. (In a normal installation this is Program Files\AeroHydro\MultiSurf6.) The executable is named Windsurf.exe. Give the DOS command: windsurf /cmdfile="c:\temp\cmd.txt"

12 MultiSurf will start up (briefly displaying an unconfigured startup screen), execute the designated script, and will then shut itself down. Following execution of the script, you can confirm that c:\ contains a new file Demo.3DA, with the date and time that the script was run. Since there was a SetPath command, there will also be a %cmdmsg.txt file that echoes the subsequent commands, and could contain useful diagnostic information.