Moving Objects in 3D Space


 ACAD only      AutoCAD provides two tools specifically designed for moving objects in 3D space: Align and 3D Rotate. Both commands are found on the Modify   3D Operations menu. They help you perform some of the more common moves associated with 3D editing.

Aligning Objects in 3D Space

In mechanical drawing, you often create the parts in 3D and then show an assembly of the parts . The Align command can greatly simplify the assembly process. The following steps show how to use Align To line up two objects at specific points:

  1. Open the Align drawing from the Chapter 16 folder of the sample files.

  2. Choose Modify   3D Operation   Align or type Al .

  3. At the Select objects: prompt, select the 3D wedge shaped object. (The source object is the object you want to move.)

  4. At the Specify first source point: prompt, pick a point on the source object that is the first point of an alignment axis, such as the center of a hole or the corner of a surface. For the Align drawing, use the upper left corner of the wedge.

  5. At the Specify first destination point: prompt, pick a point on the destination object to which you want the first source point to move. (The destination object is the object with which you want the source object to align.). This would be the top corner of the rectangular shape (see 1st destination point in Figure 16.35).

    click to expand
    Figure 16.35: 2nd destination point

  6. At the Specify second source point: prompt, pick a point on the source object that is the second point of an alignment axis, such as another center point or other corner of a surface. For this example, select the other top corner of the wedge.

  7. At the Specify second destination point: prompt, pick a point on the destination object indicating how the first and second source points are to align in relation to the destination object (see 2nd destination point in Figure 16.35).

  8. At the Specify third source point or <continue/>: prompt, you can press if two points are adequate to describe the alignment. Otherwise, pick a third point on the source object that, along with the first two points, best describes the surface plane you want aligned with the destination object. Pick the lower right corner of the wedge shown in Figure 16.35.

  9. If you pick a third source point in step 7, you'll be prompted for a third destination point. Pick a point on the destination object that, along with the previous two destination points, describes the plane with which you want the source object to be aligned (see 3rd destination point in Figure 16.35). The source object will move into alignment with the destination object.

  10. If you press at step 7, you see the Scale objects based on alignment points? [Yes/No] <N> : prompt. If you press to accept the default, the selected object(s) will move into alignment with the destination points without changing size . If you enter Y , the selected object(s) will be scaled up or down to align exactly with the two destination points.

Rotating an Object in 3D

If you just want to rotate an object in 3D space, the Modify   3D Operation   Rotate 3D option on the menu bar can simplify the operation. After you've selected this option and selected the objects you want to rotate, you see the following prompt:

Axis by Object/Last/View/Xaxis/Yaxis/Zaxis/<2points>:

This prompt is asking you to describe the axis of rotation. Here are descriptions of the options in the prompt:

Object     Enables you to indicate an axis by clicking an object. When you select this option, you are prompted to pick a line, a circle, an arc, or a 2D polyline segment. If you click a line or poly- line segment, the line is used as the axis of rotation. If you click a circle, an arc, or a polyline arc segment, AutoCAD uses the line passing through the center of the circle or arc and perpendicular to its plane as the axis.

Last     Uses the last axis that was used for a 3D rotation. If no previous axis exists, you are returned to the Axis by Object/Last/View/Xaxis/YAxis/Zaxis/<2points>: prompt.

View     Uses the current view direction as the direction of the rotation axis. You are then prompted to select a point on the view direction axis to specify the exact location of the rotation axis.

Xaxis/Yaxis/Zaxis     Uses the standard x-, y-, or z-axis as the direction for the rotation axis. You are then prompted to select points on the x-, y-, or z-axis to locate the rotation axis.

2points     Uses two points you provide as the endpoints of the rotation axis.

So far, you have had a chance to practice creating and editing 3D objects by using nearly every type of object available in AutoCAD. You might want to experiment on your own with the predefined 3D shapes on the Surfaces toolbar. In the next section, you'll discover how to generate perspective views.




Mastering AutoCAD 2005 and AutoCAD LT 2005
Mastering AutoCAD 2005 and AutoCAD LT 2005
ISBN: 0782143407
EAN: 2147483647
Year: 2004
Pages: 261
Authors: George Omura

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net