Friday, November 13, 2009

Boolean Operations In CATIA V5.

Hi all

It is a long time I did not wrote anything. I was bit busy with my personal work.

Let’s start with Boolean operations; many people don’t know how to use these 6 commands (Assemble, Add, Remove, Intersect, Union trim and Remove lump).

What is Boolean operation?
-->Boolean is an operation we can Unite two different bodies together or subtract one from another.

In Catia you can insert "N" number of Bodies, Body2, body3, body4, on.
You can insert new body by pull down menu INSERT---------> Body.
Under part body create a 100mm X 100mm sketch on XY plane and extrude it by 25mm.
Now insert another body that's body2, now create a sketch on YZ plane 50mm X 50mm and extrude using pad command around 50mm, make it mirror Extend. This block should penetrate the block which created under part body.
IMP Note: you might have observed the " + and -" symbol on body2 or body3. It’s called Polarity of that body. The Polarity of the body will be decided by the first feature used in that body. Ex: Instead of Pad if you use a pocket the Polarity will be negative, all positive feature henceforth became -ve like PAD, SHAFT, RIB...., and _ve features became positive like POCKET, GROVE, SLOT.....

Now insert another body i.e. body3 and create sketch on ZX plane, extrude using pocket it has to intersect/penetrate through both the blocks. Now Body3 having –ve Polarity”

1 Assemble.
The assemble command work on depending on the polarity of the bodies. Now select Assemble command then select Body2 (If you select Part Body you will get error) pop-up will appear, in that you can select part body, then you click on preview then Ok. Here now it will remove only Intersected material between two selected bodies. If you select body3 which is having _ve polarity, then you select either part body or body2 it will remove now, whole body3 and where this body is intersected with the selected body. If you select body2 then body3 here it will remove body2 and where this body is intersected with body3.
It’s clear that, if you select two bodies which are having same polarity It will remove only Intersected material between two bodies. If you selecting two bodies which having both +ve and –ve polarity, in this case it will remove the first selected body and where it is intersected with 2nd body.
2. Add
In add option irrespective of polarity of the bodies it will remove only intersected material between two bodies. Here the bodies may be +ve or _ve or any combination.
3. Remove
In this feature also it never bothers whether the bodies are +ve /-ve or the combination of any. It will remove first selected body and where it is intersected with the second body.
4. Intersect
To get a common material between two bodies we can use this option. Here also it won’t bother whether the bodies having different polarities.
5. Union Trim
Using this option we can remove unwanted material from both the bodies. We can use this option to create T joint for pipes.
6. Remove lump
This option is used within a body to remove unwanted lump in the body. Here we can use this option even in part body also. Assume you have “N” number of lumps in those if you don’t need some of the lumps you can select the face of the lumps which you don’t need then you can say ok it will remove all the lumps which faces you have selected. If you select both faces to remove and faces to keep and if you leave some lumps In this case it will remove the lumps which you have not selected. When you using this command I suggest please select only faces to remove or faces to keep, that is enough.
Interview questions on Boolean operations:
1. What is the difference between assemble and add.
2. What is alternative option for intersect in part design.
3. What is alternative option for remove lump in part design?
4. What is polarity of the body?
5. Is it possible to change the polarity of the body?