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Interactive viewing of objects in 3D with 3DORBIT Command

2 Comments May-26-2008 | Posted by Eren Pala | Printable Version | Level |

AutoCAD 2000 and higher versions

Greetings,

Those who are dealing with 3D know that seeing behind blocking objects or getting a suitable angle of view before rendering or during drawing is a difficult task. 3DORBIT, which is the topic of this article, is an AutoCAD tool for these kinds of situations.

Look Home>View tab in AutoCAD 2009 (of course in 3D modeling mod)

There appears a big circle and four small circles when orbit command is run. Holding from a small circle makes the drawing rotated around the axis formed between the holded circle and the opposite one. For instance, when you hold the top circle and move the mouse upside and downside, the drawing rotates around the horizontal axis. Holding outside the big circle makes the drawing rotated around the axis that is perpendicular to the screen. Holding inside it on the other hand makes the drawing rotated around both vertical and horizontal axes.

You can get the desired angle of view by the help of orbit. Yet, it mat not be enough if you plan to render the drawing. Beside you can set the angle of view, the other objects behind and in front of the subject may set to be hidden.

Figure 1

I am going to explain with an example. Let us assume, we have a kitchen drawing like the one in Figure 1 and we want to render a frame from the front view. To do this, firstly, a suitable angle of view is set but walls and cupboards block our view. Several methods can be applied for this situation. One of the practical methods is moving the objects sideways and empty our view path. But the same things have to be done for each rendering process.

Instead, open right-click menu when 3DORBIT command is active and press “Adjust Clipping Planes” (Figure 2) from the ‘More’ tab after the desired angle of view set by orbit command. The image seen on the menu is the 90° horizontally rotated image of the drawing through our angle of view.

Figure 2

The buttons in the Adjust Clipping Planes Window and their functions are listed below.

Adjust Front Clipping: Sets from where objects behind are not considered. The white line on the screen can be moved horizontally when the button is hold. The objects below the white line are excluded from the view.

Adjust Back Clipping: Sets from where objects in the front are not considered. The green line on the screen can be moved vertically when the button is hold. The objects above the green line are excluded from the view.

Create Slice: Allows movement of both green and white lines by setting a constant distance between them. You can examine sections of constant intervals.

The three buttons above work as a one, one of them can be hold at a moment.

Front Clipping On/Off: Turns Front Clipping on and off. When it is hold, the objects below the white line are excluded from the view.

Back Clipping On/Off: Turns Back Clipping on and off. When it is hold, the objects below the green line are excluded from the view.

Besides, you can get a realistic perspective view by using orbit. The first view formed with orbit is parallel perspective. You can get a perspective view by selecting ‘Perspective’ under the ‘Projection’ in the right-click menu. To increase perspective, zoom out and get a higher view angle. To do this, set ‘Adjust Distance’ under ‘more’ menu (It functions very much like zoom in and out). Below, there are three different perspective views from the same angle of view. These are;

Figure 3 : Parallel Perspective Mode

Figure 4: Perspective Mode

Figure 5: Parallel Perspective Modified by Camera Settings.

Related articles:

• Introduction to AutoCAD 2009: 5 – VIEW CUBE
• Animation in AutoCAD by using ORBIT command.
• Introduction to AutoCAD 3D

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