Boolean subtractons

E

ENOCH ARYEE

0
Boolean subtractons

Hi all.
Here is a little mystery:
I want to drill multiple holes in a box primitive.
So I placed two or more little cylinders inside the box.
Next invoke (activate) the boolean subtract tool.
I click on one cylinder....then I click on the box.
Voila...the first hole is cut (punched out}. Beautiful.

Now the mystery.
I repeat the same operation on the same box, but this time, using the second cylinder.
A second hole is cut out, but..... the first hole closes.
I have tried over and over to get two holes..in the box, but no luck. The previous hole always closes. Only the last hole remains in the box.

I am using Cheetah 2.2. .... and loving it a lot.
I am sure there is a way of punching multiple round holes in a single square box...using boolean subtract
or other methods that I am not aware of.
Any suggestions will be greatly appreciated.

Thanks. Enoch
 
Try using Make Editable (bound to command-option C on my machine, possibly by default) on the Boolean after you've performed the subtraction, and before performing the second one. It'll give you a fairly massive polygon count (it doesn't appear to be very efficient), but it'll allow you to subtract from the same object multiple times.

Hope this helps.
 
This question is quite obsolete with Cheetah3dv7 and its new Boolean library.


(Hi Enoch Aryee.
I discovered, that it can be useful to boole (connect) the holes (drills) first.
For Example: Boolean tool set to "A uniting B", put in two cylinders and doubleclick the result (the boolean tool), so that it will be transformed in a single mesh. Again choose boolean tool, set to "A+B"; throw in first boolean mesh and the last cylinder. Doubleclick the tool. Now all your drills are connected to one piece. Choose once again the boolean tool; set "A minusB). Throw in your meshed holes first, than the thing you want it divided from (excuse my english, please)
Done.
This method comes with a reward of less polygons in the resulting mesh. (See row A to B). In this case 4688 polygons (all triangled) instead of 5291. Dividing one by one, will end sometimes in unexpected output. (See row C and D; red circle)
Hope this was not too academic.
bye frank 8) )
 

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Last edited:
Hi,
the boolean creator object only substratcs on object at once. If you want to substract two cylinders for example you have to make something like the on the attached screenshot.
First substract one cylinder from the box. Than take the result from the boolean creator object and substract the other cylinder from it.

But I should probably change that behaviour so that it is possible to substract more than one object at once.

By,
Martin
 

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Hi,
Randy, Frank, and Martin.
Thanks for your various suggestions.
My problem is solved.
I can now punch as many holes as I want into a box.
Thanks again...........Enoch
 
Martin said:
Hi,
the boolean creator object only substratcs on object at once. If you want to substract two cylinders for example you have to make something like the on the attached screenshot.
First substract one cylinder from the box. Than take the result from the boolean creator object and substract the other cylinder from it.

But I should probably change that behaviour so that it is possible to substract more than one object at once.

By,
Martin
Click to expand...
Martin said:
Hi,
the boolean creator object only substratcs on object at once. If you want to substract two cylinders for example you have to make something like the on the attached screenshot.
First substract one cylinder from the box. Than take the result from the boolean creator object and substract the other cylinder from it.

But I should probably change that behaviour so that it is possible to substract more than one object at once.

By,
Martin
Click to expand...
Just a thank you for this instruction - exactly what I needed to solve one of my problems. Greatly appreciated.
 
sandpipper1 said:
Just a thank you for this instruction - exactly what I needed to solve one of my problems. Greatly appreciated.
Click to expand...
You´re digging an ancient thread from 2005.
Many things changed, evolved and added to the feature set since then. If you´re a using v7.x have a look into the Help->Cheetah3d samples->Modeling->Booleans.jas to get the idea:
Booleanv7.jpg

Cheers
Frank
 
Frank, I truly appreciate the pointers. However, the main thing I realized, after a long hard look at the release 7 example, is that it is so far past my skill level that I can't telll what's going on. I will study it, but for now, the old example I found is about all I am able to understand. Maybe some experimenting will help.
 
:oops: Hi Enoch and Sandy Pip

* a quick parsing of the hierarchic structure of Frank´s blue gadget (available from the C3D Samples menue) may help (it has to come in parts due to the limitations to images inserted in a posting):

* Top Boolean component #1:
* Box #1
* start with a parametric box
*
Box #1.png


* Box #2
* add modifier Array
*
Box #2.png


* Box #3
* add modifier Ring
*
Box #3.png


* Box #4
* add modifier Shear
*
Box #4.png




* Top Boolean component #2:
* Now to the central blob of the gadget:
* Boo #0
* start with a parametric sphere, flat front, else standard
*
Boo #0.png


* Boo #1
* add a tube, outer diameter = radius of sphere
*
Boo #1.png


* Boo #2
* stick these into a subtractive Boolean, ie ball - tube to obtain a sort of capsule
*
Boo #2.png
 
* To further modify this object:

* Boo #3
* add a torus (+ array modifier) on the same level
*
Boo #3.png


* Boo #4 & #5
* add a ball (+ ring modifier)
*
Boo #4.png

*
Boo #5.png


* Boo #6 & #7
* add a capsule (+ ring modifier)
*
Boo #6.png

*
B00 #7.png


* Boo #top
* stick the objects (box, sphere, etc) into an additive Boolean
*
Boo #8.png


* Notes
* I have slightly edited the C3D sample (layers only) to to differentiate the various types of objects used in it: white = polygon object, grey = spline, red = Boolean, blue = modifier, green = creator).
*
* In case you do not yet know, you can disable / enable modifiers and creators by clicking on the respective icons in the left margin of the object browser´s panel.
* Modifiers are executed in top-down sequence; eg, there is a difference between box + array + ring vs box + ring + array.
* Note that this model, despite looking quite complex, uses parametric objects only. None of the components are in destructive edit status. As a result, you can customise any of the components quite easily if required.
 
* Notes
* I have slightly edited the C3D sample (layers only) to differentiate the various types of objects used in it: white = polygon object, grey = spline, red = Boolean, blue = modifier, green = creator).
*
Gadget #1.png


 

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