In this tutorial we are going to look at the display of geometry in ICEM Surf. We will look at the Display menu which controls line and point styles as well as shading. We will also look at how we can control the quality of the graphics.
Go to File-open. Pick project ICEMSURF-tutorial and the database DISPLAY-OBJECTS.
This database contains a range of object types that you might see in an ICEM Surf database.
Go to the Display menu from the service functions. Alternatively you can access Display from the top menu bar or you can use the shortcut Ctrl+A.
It is good practice to keep the service menus including display in the lower left corner of the screen.
Make sure that the menu is fully open. If not then click on the arrow.
Make sure that Selected is off and Apply Immediately is on. This will ensure that any changes you make to the menu are immediately reflected in the graphics. There is never any real need to turn this off.
The Display menu is arranged in 5 blocks on the right hand side, one for each object type: points, raw data, curves, surfaces and scan. These blocks are arranged in 4 columns: object types, line/point display, labels and colours.
Let’s look at point objects first. The tick means that we can switch the display of points on or off
In the Line/Point column we can change the style of the points using the pull-down menu.
In the Labels column we can choose how or whether we display the point numbers. It is very rare to need to know the point numbers so usually we don’t need the label. However, it can be useful if the points are difficult to see amongst a lot of other geometry.
In the last column we can change the colour of all the points. Clicking on the colour swatch accesses a range of colours.
If you want to change the available colours then you can do this through the Display-Colours menu from the top bar.
The next block in the Display menu is for raw data.
In the Line/Point column we can change the line style in the first pull-down and the point style in the second pull-down.
The displayed rawdata points represent the actual XYZ values of the rawdata.
In the Labels column the first pull-down allows us to display the label on each raw data segment. The label shows the contour name and segment number.
The “123…” icon allows us to toggle the raw data segment point numbers on and off.
When the Segment button is clicked on then the end points of raw data segments are shown. This and/or the raw data labels may be useful on occasions when, for example, you need to connect several raw data segments together.
Once again the colour swatch in the 4th column can be used to alter the colours of all raw data.
The Curves block is next. The Segments tick box will switch all curve segments on or off.
Switch CtrlP on to see the control points of all curve segments.
In the Line/Point menu we have a NURBS tick box. When ticked, NURBS and BSpline objects will be shown in red by default. It is recommended that this is always on as NURBS and BSplines are generally best avoided in ICEM Surf so it is as well to be alerted when they appear; for example within imported data.
Below the NURBS box there are pull-downs for the line-styles of curve segments and the line-styles of the control point hull i.e. the lines that connect the control points.
I would recommend setting the segment line style to solid and the control point hull line style to dotted.
Next to the line-styles there is the point style pull-down for the segment end points. I recommend that you set this to X. Below this there is the point style pull-down for the curve segment control points. I suggest that you set this to O.
In the Labels column we can turn labels on and off. The first label box is for displaying the curve name and curve segment number. This may be useful occasionally.
We can also put number labels on the control points. This is seldom useful.
If there are NURBS or Bspline curves in the model then Segment will show us the internal knot points of these curves. The knots are places where the curve has a reduced level of continuity such as tangency only. They enable NURBS or Bspline curves to describe complex shapes within a single curve segment.
The colour swatches enables us to apply different colours to curve segments and the control point hulls.
Moving further down the menu we come to the Surfaces block. This controls the display of patches and faces.
Edges toggles the edge display on or off.
CtrlP toggles the internal control points on or off.
Edge Ctrlp toggles the edge control points on or off.
Iso-Curves controls the display of internal iso-curves.
In the Line/Point column we can specify that NURBS and Bsplines are highlighted in red by ticking on the NURBS box. As for curves I would recommend keeping this ticked on at all times so that you’re alerted about the presence of any NURBS or BSplines.
The line display of the edges, control point hulls and iso-curves is controlled with the pull-downs below. The control point symbols are accessed through the point pull-down to the right.
In the Labels column the first label pull-down toggles the display of the patch or face numbers. This is sometimes useful.
Segment will show the knots or segment boundaries of any NURBS or BSpline surfaces. This is useful before you convert NURBS or BSpline surfaces to Bezier.
The little angle symbol when ticked on shows the u direction of patches. You can think of the graphic on the patch as a half-arrowhead pointing from in the u direction.
This can be helpful when you are trying to put Diagnostic-Curvature on several patches and you need to align the u and v directions on all the patches. It’s also useful in understanding the All function in the Patch-Modify-CtrlP menu.
The remaining labels are for control point rows, points and iso-curves. These are rarely used.
The U and V values define the number of iso-curves to be displayed in each direction.
The colours of the edges, control points and iso-curves can be set using the colour swatches.
The last block is for scan data.
Scanline is only relevant for structured scan data usually created by a mechanical measurement device. It’s very rare to need this function as modern scan data is triangulated.
Points refers to the digitised locations of the scan.
Facets refers to the triangular facets of the scan
In the Line/Point column we can control the display of scan lines and points.
In the Labels column we can switch labels on to show the scan set and number information.
Reduced is very useful as it means that the points displayed are less dense so that the graphics area is less cluttered. It does not reduce or alter the data in the database – only how much data is shown in the display.
Segments show end points of scan-lines which is not really relevant any longer.
The type of facet display is defined in the drop-down menu. Flat shows the facets as flat shaded triangles. Gouraud (pr: goo-row) blends the triangles. Perhaps surprisingly Gouraud is graphically less demanding than Flat. Flat should be used when you want to see precisely where the scan data points are. Edge shows only the edges of the facets. Shad edge applies shading to the edge lines.
As always, there are colour swatches for the scan in the last column.
In the bottom left corner of the Display menu there is an option to put anti-aliasing on curves. Anti-aliasing is a way of smoothing the display of curves by adjusting the intensity of individual pixels.
Shading switches surface shading on and off.
Hidden line, which is only available when Shading is on, results in a wire-frame display of the surfaces but hides any edges which would be obscured in reality.
So far we have looked at geometry which is not actively selected in any function.
Let’s have a look at a selected curve segment for example. If we pick Modify-Curve-Ctrlpt and then pick a curve segment we will see that the display of the curve segment changes. The way in which this selected curve segment is displayed is defined in the Display menu.
There is another layer to the Display menu which is accessed by picking Selected at the top left corner of the menu.
Looking at the Curves block here we can see the definition for selected curve segments. I suggest changing the settings so that the curve segments have solid lines and the control point hulls are dotted. I usually set the segment end points to be X and the curve control points to be O.
Notice that all selected objects are white. The colour swatches are not available to pick here. To change the colour of selected objects go to Windows-Preferences-Selection and change the colour of Highlight1. I sometimes use this when working with a light-coloured image in the background. Then setting the highlight colour to a dark colour or black makes the selected objects easier to see.
With Selected picked in the Display menu you can set the rest of the object types to whatever you need.
You may have noticed that the patch and face edges and curve segments are rather facetted.
In order to improve the quality of the lines and surfaces then pick the Set Tessellation icon. Normally we want the tessellation of the shading and the wire frame to be the same, so tick Equal Tolerances on. In the Shading text box the lower the number the more refined the graphics. Setting it too low will slow the graphics down considerably, depending on the speed of your machine. 0.005 usually works well. The number of triangles shown refers to the scan data facets and also the shading of surfaces. When shaded, surfaces are approximated by a triangulated display.
Returning to the Display menu, we have now set the display for all the non-selected and selected objects. We have also defined the tessellation in the tessellation menu. In order to save these settings we use Save and assign a name such as DISP1. This then appears in the lower scroll window of the menu. These are the user-defined display variants. The display variant DB is that of the model when it was last saved.
In the upper scroll window we have system-defined display variants. Double-clicking on one will activate the relevant display settings.
If we double-click on the variant DISP1 that you previously saved we will go back to those settings.
Notice that the user-defined variants can be renamed and deleted if necessary.
It is a good idea to set up your own variants which you can use from one model to the next.