Drawing in the Scene

In Leapfrog Works, you can draw polylines to define many surfaces, including lateral extents and contact surfaces. You can also use polylines to make adjustments to surfaces and create new GIS lines.

This topic describes drawing polylines in Leapfrog Works. It is divided into:

• The Drawing Toolbar
• Drawing Hotkeys
• Drawing 3D Lines
• Drawing 2D Lines
• Node Snapping Options
• Editing a 2D or 3D Polyline
• Polyline Properties
• Tangents and Ribbons
• Drawing Points

For information on importing and exporting polylines, see Polylines.

When drawing in Leapfrog Works, you can draw on surfaces or on the slicer.

• If you are drawing on surfaces (), the line will be in 3D.
• If you are drawing on the slicer (), the line will be in 2D and locked to the plane it was drawn in. It can be converted to a 3D line.

When you start drawing a polyline, drawing tools are added to the scene window. If you are drawing a GIS line or if the slicer was already in the scene, the drawing mode will be set to be on the slicer. Toggle between the two options using the toolbar buttons:

When drawing and otherwise working with the polyline, hints are displayed in the scene that show what actions are currently possible:

For example, if the mode is set to draw on the slicer (), you will be warned if the slicer is not in the scene:

The Drawing Toolbar

The Draw lines () and Draw points () tools are used to create new lines and points. The tools in the second row are for controlling whether the polyline is drawn (on the slicer () or on surfaces ()). The node snapping selector () allows you to specify the way a new node snaps to existing objects. The Select list lets you select different parts of the polyline.

The other tools are for working with selected parts of the polyline:

• Making line segments straight () or curved ()
• Adding nodes () to lines
• Adding tangents to lines or reorienting selected tangents ()
• Flipping selected tangents and disks ()
• Add disks to points ()
• Converting a 2D polyline to 3D ()
• Setting the slicer to a 2D polyline ()
• Simplifying the line by reducing the number of nodes ()

There are also buttons for undoing () and redoing actions (), as well as saving the polyline () or deleting selected parts of it ().

Drawing Hotkeys

Use the following keyboard shortcuts while drawing:

Key(s)	Action
Ctrl+5	Draw lines ()
Ctrl+6	Draw points/disks ()
Ctrl+S	Save ()
Ctrl+W	Close editor ()
Ctrl+Z	Undo ()
Ctrl+Y	Redo ()
Delete	Delete the selected segment, node, tangent or disk ()
X	Draw/move on slicer ()
Shift+X	Draw/move on objects ()
Q	Make segments curved ()
Shift+Q	Make segments straight ()
Shift-A	Add node ()
A	Add/reorient tangent ()
V	Flip tangent/disks ()
Shift+D	Add/remove disk ()
Shift+E	Make selected line 3D ()
Shift+W	Set slicer to selected 2D line ()
Shift+S	Simplify the line by reducing the number of nodes ()
Alt+S	Toggle snapping
Alt+N	Snap to polyline nodes ()
Alt+E	Snap to mesh edges ()
Alt+V	Snap to mesh vertices ()
Ctrl+A	Select all
Shift+Ctrl+Alt+L	Select all lines
Shift+Ctrl+Alt+T	Select all tangents
Shift+Ctrl+Alt+P	Select all points without disks
Shift+Ctrl+Alt+D	Select all points with disks

Drawing 3D Lines

Polylines are made up of nodes, which are added where you click in the scene using the Draw lines () tool. This is a 3D polyline, which is indicated in the scene by the dashed line. The cursor is currently over a node.

Click to select a node and drag to move it in the scene parallel to the screen.

If you select a node, then hold down the Ctrl key while moving the node, it will snap onto surfaces in the scene.

When you click to add a node, dragging the mouse before releasing the button lets you control the curvature using bezier curves. Use this to get at least the approximate shape of a curve; later on you can adjust the position of nodes and the bezier handles to improve the shape.

When you start drawing a polyline, a tangent is automatically added to the first node. This is oriented in the direction of the camera, and you will need to rotate the scene to see the tangent cone and the direction it is pointing.

There are also bezier control points on curved segments. These are used to control the curvature of the segment, and you can click on a control point and drag it to change the curve of the segment:

Drawing 2D Lines

Working with a 2D polyline is similar to working with a 3D polyline, except that drawing is restricted to the 2D plane set by the slicer. A 2D polyline is indicated in the scene by an unbroken line:

The cursor is currently over a node.

To convert a 2D polyline into a 3D polyline, double-click on the line to select the whole line, then click the 3D polyline button ().

Node Snapping Options

With the node snapping selector (), you can choose how a new node snaps to existing objects. You have the following options:

• Snap to polyline nodes (for 2D and 3D polylines)
• Snap to mesh edges (for 3D polylines only)
• Snap to mesh vertices (for 3D polylines only)

With a node snapping mode selected, the new node will snap to the object when you click to locate the node. To see the effect of snapping, zoom in close:

As you get close to an object the new node is able to snap to, it will pull the new node to the object like a magnet. When Snap to mesh edges or Snap to mesh vertices options are selected for 3D lines, if an object is not close enough, the cursor and the hint text will indicate that no object is under the mouse cursor. As you approach an edge or a vertex, the cursor will pull to that edge or vertex to make clicking on the snap-to object easy.

Editing a 2D or 3D Polyline

When you have finished drawing, right-click to end the polyline. Switch to the Select tool () to make changes to the polyline.

• Click on a node to move it.
• Click on a segment away from a node and drag it to change its curvature.
• Click on one or more segments, then make them straight () or curved ().
• Select a point on the polyline, then click () to add a node.
• Select a point on the polyline. The point selected is indicated in the scene by a red cone. You can then click () to add a tangent oriented in the direction of the camera.
• Select a tangent and click () to change the orientation of the segment to that of the camera.
• Select a tangent and click () to flip it.

Begin drawing again by selecting the Draw lines button (). To continue from an existing node at the start or end of a polyline, click on the node.

Use as many nodes as necessary to draw the polyline. You can later reduce the number of nodes using the Simplify polyline tool (). Each time this tool is used, Leapfrog Works attempts to halve the number of nodes on the select segments:

Although you can make the line curved while adding nodes, an easy way to draw a curved polyline is to simply click to add a series of points. Set the curvature of the whole line by selecting all segments and then clicking the Make selected segments curved button ():

You can then make any adjustments to the curves required by dragging the segments or using the bezier control points.

Polyline Properties

In the shape list, you can control the colour of the positive (red) and negative (blue) surfaces of the line and of the line itself (green):

With the controls in the properties panel, you can change the size of different parts of the polyline to make working with the polyline easier.

For Ribbon width and Point size, the setting is, by default, in pixels, but both can be displayed in real-world size by unticking the pixels box, which may make editing the polyline easier in some circumstances.

You can also choose whether or not to show tangent cones and bezier control points.

Tangents and Ribbons

The Surface ribbon () and Normal ribbon () help you to determine the orientation of the polyline in the scene. The surface ribbon reflects the orientation of the polyline and the normal ribbon is perpendicular to the surface ribbon.

For example, click on the Surface ribbon button () to determine which side of the polyline is positive (red) and which side is negative (blue):

If you are having trouble seeing the ribbons, you can change their size using the Ribbon width control in the properties panel.

When you first draw a polyline, it has only one tangent, located at the first node and oriented in the direction of the camera. You can add more nodes by clicking at a point along the polyline and then clicking the Tangent button (). A tangent is added to the polyline, which is updated to reflect the new information. The tangent’s orientation is taken from the camera angle. To reorient a tangent, click on it in the scene, change the camera angle to reflect the orientation you wish to set, then click the Tangent button ().

You can also flip selected tangents by clicking on the Flip tangents and disks button ().

You can add as many tangents as required, although it is best to keep them to a minimum.

Drawing Points

Polylines can also include points, which are drawn using the Draw points tool (). Clicking adds a point, and clicking and dragging adds a point with a normal. Normals are shown in the scene as disks intersecting the points. The scene below shows one point with a normal and one without:

To move a point without a normal, switch to the Select tool (). Click on the point and drag it. To add a normal to the point, click on it in the scene and click the Add disk button ().

To edit the orientation of a point with a normal, click on it in the scene. There are two rotation modes, and a click on the disk will change between modes. In one rotation mode, yellow and blue arrows show how dragging the disk will change the dip and azimuth of the disk. The yellow arrows indicate the direction of rotation when you click-and-drag the disk. Change the position of the pointer on the disk to switch the rotation selection to the other pair of arrows. In the other rotation mode, an extended translucent disk extends out from the point at right-angles to the point’s disk. Around the edge of the disk are four blue arrows indicating the rotational direction. Click-and-drag the point’s disk to adjust the disk angle. Change the position of the pointer on the disk to change the angle of the rotation plane on the point’s disk.

You can also change the orientation of a disk by drawing over it. To do this, make sure the Draw points tool () is selected. Hold the cursor over the point you want to edit. The cursor will turn green to indicate that you can adjust the disk’s angle. Drag to adjust the angle and release the mouse button when finished.

You can also flip selected disks by clicking on the Flip tangents and disks button ().