Centre
closest distance>> 0 1 1 Enter end point >> 1 1 0
The normal to the arc can be chosen as the screen normal by simply left-clicking in the graphics area.For the specification of the normal anchor point, start and end points, it is possible to attract the cur- sor to existing points, curves or surfaces. This feature is very interesting since it allows to connect curves together and to create T junctions. By default this attraction is enabled. To toggle the attrac- tion to points, press <a> in the graphics area. Similarly, to toggle the attraction to curves or sur- faces, press <c> or <s> respectively. When the cursor is attracted to an entity, a filled-in circle is displayed. The attraction works on:
—point attraction: Cartesian points and curves end points if they are visible,
—curve attraction: visible curves,
—surface attraction: visible surfaces,
—vertices and fixed points. This attraction always work and cannot be deactivated.
The point, curve or surface attraction feature is activated or deactivated by pressing respectively <a>, <c> or <s> repeatedly, while the cursor is in the graphics area.An angle can be specified in place of the end point by pressing <p> when the start point is entered. The following prompt will appear:
Enter angle
>> 45
Enter the desired angle and press <Enter>.
To quit this tool without creating an arc, press <q> or the right mouse button. Example:
To draw a circular arc from (1,1,0) to (0,1,1) with centre (0,1,0), enter the following: plane normal (0,1,0)
anchor point (0,1,0) start point (0,1,1) end point (1,1,0)
Notice that entering (0,0,0) for the anchor point would give the same result. Indeed, (0,0,0) is located on the same arc normal than (0,1,0).
Arc->Normal-Point-Point-Radius. This menu option is used to create circles or circular arcs
through two points, with a given radius and perpendicular to a normal. The following inputs are requested from the user:
• Circle/arc normal,
• Start and end point,
• Circle/arc radius,
All these data (except the arc position) can be entered either through the keyboard input area or with the mouse. The normal to the arc can be chosen as the screen normal by simply left-clicking in the graphics area.
For the specification of the arc start and end points, it is possible to attract the cursor to existing points, curves or surfaces. This feature is very interesting since it allows to connect curves together and to create T junctions. By default this attraction is enabled. To toggle the attraction to points, press <a> in the graphics area. Similarly, to toggle the attraction to curves or surfaces, press <c> or <s> respectively. When the cursor is attracted to an entity, a filled-in circle is displayed. The attrac- tion works on:
—point attraction: Cartesian points and curves end points if they are visible,
—curve attraction: visible curves,
—surface attraction: visible surfaces,
—vertices and fixed points. This attraction always work and cannot be deactivated.
The point, curve or surface attraction feature is activated or deactivated by pressing respectively <a>, <c> or <s> repeatedly, while the cursor is in the graphics area.Once the start point is entered, it is displayed in a filled-in circle and a semicircle is drawn through this start point and the cursor (Figure2.5.2-3). Moreover, a line representing the radius and a cross representing the center are displayed; the corresponding values of the radius and center are shown in the information area. When the end point is entered, it is also displayed in a filled-in circle.
FIGURE 2.5.2-3 Arc representation before its creation
FIGURE 2.5.2-4 Six arcs drawn through two points with a given radius
If the radius is entered through the keyboard input area, it is possible that the value entered is too small (if value is lower than half distance between start and end point), in which case a warning message appears. When the radius is entered, the sense of the circular arc can be chosen by pressing <o> repeatedly. In fact, there are six possibilities to draw an arc between two points and with a given radius, which includes two possibilities of complete circle, as shown in Figure2.5.2-4. Once the correct sense is chosen, simply click on the left mouse button to complete the arc creation. To quit this tool without creating an arc, press <q> or the right mouse button.
Arc->Point-Point-Point. This menu option is used to create circular arcs through three points. The
following inputs are requested from the user:
• Start point,
• End point,
• Middle point.
All these data can be entered either through the keyboard input area or with the mouse.
During the specification of the points with the mouse, it is possible to attract the cursor to existing points, curves or surfaces. By default this attraction is enabled. To toggle the attraction to points, press <a> in the graphics area. Similarly, to toggle the attraction to curves or surfaces, press <c> or <s> respectively. When the cursor is attracted to an entity, a filled-in circle is displayed. The attrac- tion works on:
• visible points and curves end points,
• visible curves,
• visible surfaces,
• vertices and fixed points. This attraction always work and cannot be deactivated.
The point, curve or surface attraction feature is activated or deactivated by pressing respectively <a>, <c> or <s> repeatedly, while the cursor is in the graphics area.The start and end points must be specified first and are displayed in a filled-in circle. When both points are specified, a circular arc is drawn between the start point, end point and the current cursor position, representing the mid point (Figure2.5.2-5). Moreover, a line representing the radius and a cross representing the center are displayed; the corresponding values of the radius and center are shown in the information area.
It is possible to get a complete circle by pressing the <o> key. Pressing <o> a second time comes back to the circular arc mode.
FIGURE 2.5.2-5 Circular arc representation before its creation
Entering the mid point will complete the circular arc (or circle) creation. To exit the tool without creating an arc, press <q> or the right mouse button.
2-5.2.3 Surface page
a) Lofted
This command is used to create a NURBS surface interpolating a set of selected curves. The orien- tation and the order of the selected curves are taken into account to define the surface.
FIGURE 2.5.2-6 Curves order and orientation when creating a Lofted surface
An automatic creation of internal surface at Z-constant has been implemented and available thanks to the Marine module in the Plugins menu. See 62 for more details.b) Coons
This command allows to create a NURBS surface from four selected curves, using a bilinear inter- polation. The four curves should define a closed region and should have the following orientation:
FIGURE 2.5.2-7 Curves order and orientation when creating a Coons surface
The four curves must also be selected as indicated in the figure (curve 1 first,...).
c) Import
This button offers the possibility to import an STL surface as an internal surface into HEX- PRESS™.
This command also allows to import ".dat" geometry files already exported within HEXPRESS™ with the following command.
For multidomain case, the internal surface will be part of the active domain when importing the file.d) Export
This command allows to export ".dat" geometry files that can be imported within HEXPRESS™ with the previous command.
1 2 1 2 3 4