AboutCAD: 09/28/11

Differences Between Extrude, Revolve and Presspull

Many ways to create 3D objects, among the functions of command "Extrude", "Revolve" and "Presspull", each has advantages and disadvantages depending on the requirements and techniques in use, and depending on the object that will do you.

3D objects are generally derived from 2D objects, then extrude do with technique, or presspull Revolve, a special command presspull present only in the latest version of Autocad version, but if extrude and Revolve has existed on older versions.

This is characteristic of each function.

"Extrude"

    1. Extrude an object that will have to form a single entity, eg rectang, ellipse or circle.
    2. Objects that have not been a single entity, must first be done pedit or region.
    3. Extrude can be done against an irregular object, or a complicated shape.
    4. Extrude can be done by following the desired line (path), examples of hurus "S".
    5. Could form the slope (taper) when the extrude.

Figure 1.

2D objects that extrude and extrude in the taper.

"Revolve"

    1. Extrude an object that will have to form a single entity, eg rectang, ellipse or circle.
    2. Objects that have not been a single entity, must first be done pedit or region.
    3. It is suitable for forming objects such as bottles, glass or tire and rim.
    4. Revolve can be done to the axis "X" and "Y"

Figure 2.
Revolve 2D Objects in the axis X or Y and to help lines.
"Presspull"

1. Can be done on an object that has not been a single entity.
2. Can make holes (press) or to make things stand out (pull).

Figure 3.
2D object in the middle gap presspull select objects.

Figure 4.
3D objects in the press and that the full.

Tip : How to Maintain Attribute remain in the Middle Block

On the tip of this dynamic block, we make some elements of the picture and add attribute in the middle of the block. We need to add action to block this stretch, because we want to change the size of the block. The challenge is we need to keep the attribute remains in the middle of the block. There are two ways to do this: first we can let the attribute remains in the middle block to block and stretch the sides. Or the second way: we are to stretch to one side and at the same time move the attributes but still in the middle.

Let's try it. I use a simple dynamic block: room tag.

Create Attribute

Makes essentially the same attributes, we use ATTDEF.Untuk it easier later on, arrange for justification to the center.

One more thing : make sure the lock position is active. Some dynamic block action will not work if it is not set to lock.

Alternative 1 : stretch in both directions

This makes it fairly easy. You can change the parameters of the base location to the midpoint. Then add two stretch action on both sides.

Alternative 2 : Add a stretch action and move

If you create a dynamic block that is quite complex, you may not want to stretch it in both directions. Suppose you want to create a table that also has an array of action. When the size of the table changes, you also want to change the number of seats. You can also see some other examples of dynamic blocks in AutoCAD e-book Best Practices (Indonesian language).

In this situation, it would be easier if we are to stretch in one direction only. To keep the attribute remains in the middle block, we add one more to move the action attribute.

Remember: an attribute to be moved half the distance from the block size changes. If kia stretch of 100, then the attribute must switch 50, to stay in the middle. To achieve this, select the move action. Change in the Properties palette is the distance value multiplier to 0.5.

RELATED POSTS

Tip : Select All Horizontal and Vertical Lines on In Pictures

There are times we need to select all horizontal or vertical lines in an image. It is not easy and can be tedious, especially if we work on the rather complex picture. We can use QSELECT to do this job quickly!

How do you use? Easy. Vertical lines means the lines have the same X value, while the horizontal line have the same values of Y!

Take a look at QSELECT. Change the object type to the line, the properties to the delta X (or Y delta, depending on the type of line you want to choose), and change the value to 0. Click OK, and you're done!

Note:

You can perform further filtering. You can just select all the vertical lines in Layer A, or a horizontal line that has a red color and length of 100 units, and so on. You know how right?

RELATED POSTS

Wednesday, September 28, 2011

Differences Between Extrude, Revolve and Presspull

Tip : How to Maintain Attribute remain in the Middle Block

Tip : Select All Horizontal and Vertical Lines on In Pictures