Object handles allow you to manipulate object properties directly - pretty much the same way people tend to manipulate objects in real life. For example, you do not have to push some 'move' button somewhere on your desk to enter 'move paper' mode or tool. You just grab the paper and move it.
Object handles in Realsoft 3D work the same way. They provide direct control over object properties like position, size and orientation.
All geometric objects have nine transformation handles, which allow you to control position, size and orientation. When selecting multiple objects the handles of the first selected object are shown.
When you 'drag' (press the left mouse button while moving the mouse) one of the transformation handles, the corresponding transformation tool is activated. The transformation follows the mouse movement during the drag operation.
To move a rectangle, follow these steps:
Create a small rectangle and select it. You can now see the three perpendicular lines, which are the handles to move the rectangle.
Move the mouse over the 'x' axis handle (the red axis), press the left mouse button and hold it. Note: when the mouse is positioned over the handle, the cursor changes to reflect the function of the handle. Also the status bar informs you about the purpose of the handle.
The rectangle is moved along its 'x' axis as you drag the mouse. When a desired new position is reached, release the mouse button to accept the tool. Hitting the 'Esc' key during the dragging cancels the operation.
To rotate the rectangle just drag one of its circular rotation handles.
To scale the rectangle drag the end points of the move handles (the perpendicular lines). The scale handles are marked with small diamonds.
Note: the color of a handle corresponds to directions of the object space as follows:
X - Red
Y - Green
Z - Blue
You can also activate a transformation tool by clicking the corresponding object handle. In this case the clicked handle acts as a 'constraint' for the tool. All the tool options are shown and you will be able to use numeric interface, dragging and other snapping techniques.
Let us see what is possible in this mode but first a quick excursion to a useful technique called 'point snapping':
To 'point snap' specific points of an object, move the mouse above and to the left of the point and press and hold the left mouse button. While holding the left button down move the mouse downwards and to the right (drag the mouse) until the point is inside the small rectangle that is drawn. Now release the mouse button. This handy operation is called 'point snapping' and can be used to snap the mouse position exactly to a desired point position.
Now we will perfectly align two rectangles using the "drag selection" technique:
Create two rectangles say 'red' and 'blue'.
Now we want to move the red rectangle so that the upper horizontal edge of the red rectangle is aligned to the lower horizontal edge of the blue rectangle.
Select the red rectangle and click the 'y' translation handle (the green axis). The 'y' handle becomes thicker to indicate that it is selected and the Move tool is activated. The rectangle now moves on its 'y' axis as you left click and move the mouse.
Drag select the top right corner of the red rectangle using point snapping . Then drag one of the bottom corners of the blue rectangle to define the target position . The two edges of the rectangles are now precisely aligned!
Now scale the red rectangle so that its top right corner matches the bottom left corner of the blue rectangle.
Click the end point of the 'x' translation handle (the red axis). Note: when you move the mouse over the end point handle, the cursor changes. This, in addition to the help text in the status bar, indicates that the scale operation will be activated if you click the mouse.
Select the top right corner of the red rectangle using point snapping. Then drag the left bottom corner of the blue rectangle the same way. The right edge of the red rectangle is now perfectly aligned with the left edge of the blue rectangle!
When rotating and scaling objects, it is often necessary to define an appropriate center for the transformation.
When activating the Scale or Rotate tool from the Toolbar this center point is defined by the first mouse click. When using object handles the origin of the object space is used as the center of transformation. Many program call this 'center of transformation' point the Pivot Point.
To change the pivot point you can either drag the pivot point or click it. Dragging is perhaps faster to use but by clicking the pivot point you can use point snapping and other snapping methods for more precise results. Moving the pivot point means that you move the object space origin.
Now move the pivot point of the 'red' rectangle exactly to the left top corner:
Move the mouse over the pivot point handle and left click to activate the Move tool with 'Handles' option. Hitting the 'Insert' key also activates this "move pivot" mode.
Use point snapping to pick up the pivot point so that you can position it exactly at the desired point. Now the object handles move while you move the mouse.
Then drop the pivot by point snapping the top left corner of the rectangle. This accepts the Move tool and the pivot point is now located exactly at the top left corner of the rectangle.
The 'Shift' key is perhaps one of the most often needed modifiers. The purpose of this modifier depends on the tool.
Uniform scaling: If you scale an object, the Shift key acts as a 'uniform' modifier. By dragging any of the three scale handles while holding down the Shift key, you can scale them uniformly in all the three dimensions. This is a common practice in many other applications as well, so it should be easy to remember.
For example, to make the red rectangle bigger:
Select the red rectangle and press down the 'Shift' key.
Drag a scale handle, while still holding down the Shift key.
The rectangle maintains its proportions in all three dimensions during the scale operation.
For example, to rotate the red rectangle 90 degrees:
Hold down the Shift key
Move the mouse cursor over the blue circular rotation handle and drag (move the mouse while holding down the left mouse button) the mouse around the pivot point while still holding down the Shift key. You will only be able to rotate the rectangle in 45-degree steps and therefore 90-degree rotation can be easily achieved.
Duplicating and instancing: Many tools in the program use 'Ctrl' key as a 'copy' modifier. The 'Alt' key can be used for instancing objects. This is also true for object handles. Holding down the Ctrl key while dragging any of the handles first duplicates the selected objects and then applies the handle operation to the duplicated object. The original object is not affected.
Let's create four red rectangles.
Select the red rectangle (if not already selected) and press down the 'Ctrl' key.
Drag the 'x' move handle (the red axis handle) while pressing the 'Ctrl' key to duplicate the rectangle and move the new rectangle sideways. Repeat this operation three times to get three new rectangles.
There are many other useful modifiers which can be used for making object handles even more powerful. However, they are beyond the scope of this tutorial.
It is often necessary to apply exact transformations to objects. Let us assume you want to rotate the red rectangle by exactly 23.4 degrees.
Make sure the numeric window is opened. If not, select the pull-down menu 'View/Numeric Window' to open it. You can now see how coordinates run on the numeric window as you move the mouse on the view window.
Select the red rectangle and double click one of its rotation handles. You can either double click the rotation handle or just click it two times. If you now move the mouse, you can see how the rotation angle field in the numeric interface shows you the current rotation angle.
Enter 'Numeric' mode by hitting the 'n' key. This activates the 'Angle' field in the numeric window. Alternatively, you can activate the 'Angle' gadget by clicking it with the mouse. Type the desired rotation angle of 23.4 degrees and hit the 'Enter' key to accept the rotation.
The selected red rectangle is rotated by exactly 23.4 degrees.
Also the Move and Scale tools support the numeric interface. However, when activated through handles, only one-dimensional scale and transformation factor needs to be defined. For example, to move the red rectangle 0.1 meters along its 'y' axis:
Click the green 'y' axis of the rectangle twice. The numeric window now shows you the displacement along the 'y' axis.
Hit the 'n' key and enter '0.1' in the Move1D field. Then press the 'Enter' key. The object is moved 0.1 meters along the axis.
Object handles allow you to scale and rotate objects easily provided that you want to apply the modification about the pivot point. As soon as you want to apply transformation about an arbitrary point, you have to move the pivot point. Moving pivot point frequently just to get an object rotated sounds like a lot of work and can soon become a 'major pain'. Fortunately, there is a faster way.
To rotate a rectangle about its left top corner:
Select the rectangle.
Click the desired rotation handle as usual. This activates the rotation tool about the pivot point. However, the tool activated by the rotation handle is the standard Rotate tool i.e. the very same tool you can activate through the toolbar or by hitting the 'r' shortcut key.
All transformation tools support 'Go Back' function, which allows you to re-enter any of the input points if needed. Therefore, it is possible to re-enter the rotation center. Select 'Go Back' from the view's pop-up menu or hit the 'Backspace' shortcut key.
You can now click or drag anywhere to define a new center of rotation. The transformation is still locked to the original, suitable rotation plane.
You can multi select any number of objects. In this case, only the first selected object provides the transformation handles so that the numerous handles don't clutter the entire view window. The handle of the first selected object transforms all the selected objects.
By controlling the selection order you can define a desired transformation space for modifying all the selected objects. For example, you can even add special 'reference' objects whose only purpose is to provide appropriate transformation spaces for the actual objects.
If you frequently have to transform objects in three special directions, just create three dummy objects whose object spaces match those directions. Then multi select the desired orientation object first and then the actual objects you wish to transform. The first selected object provides you conveniently oriented transformation handles.
Note: you can also change the object selection after you have activated a tool by clicking a handle. This is a very powerful feature, too. Let us demonstrate this with a simple example:
The goal is to rotate the red rectangle using the handles of the blue rectangle. You can, of course, move the pivot point of the red rectangle over the blue rectangle and then use the rotation handles to rotate the object. But this is not the same if the blue rectangle has a different object space orientation. However, there is an easy way to accomplish that: Just select the blue rectangle and click its rotation handle. This activates the Rotate tool and uses the pivot point of the blue rectangle. Then, using the select window, select the red rectangle. Then continue the rotation as usual. You have used a rotation handle of the 'blue' rectangle to transform the 'red' rectangle!
All geometric objects share a number of common properties, such as position, orientation and size. Correspondingly, they all support a set of common handles described above.
Additionally, geometric objects can define handles, which are specific to the object class in question. These object specific handles are shown when you enter the 'Edit' mode. Such special handles can activate arbitrary object specific tools.
Select the red rectangle.
Select 'Edit' from the view's popup menu or click the 'Edit' gadget in the tool control bar. The transformation handles disappear and three small point handles (little squares) appear.
Move the mouse over the handle in the top right corner. Press the left mouse button and drag the handle to a new position.
Leave the edit mode by deactivating the 'edit' option from the popup menu or the tool control bar.
The object specific handles of a rectangle are the 3 points defining the geometry of the rectangle. You can use them to 'point edit' the rectangle. You can naturally also apply the usual tools like move, rotate, etc. and techniques like point snapping to these handles.
You can find more information about object specific handles from the tutorials describing geometric objects.