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Boolean "Keep Tool"

allen_stewartallen_stewart Member Posts: 32

Hello Everyone,

Im new to onshape and I am trying to learn all the features.  Can someone explain to me what the "Keep Tool" with regards to the Boolean subtract is?  Is there also a in-depth explanation of all the tools and features?

thank you

Best Answers


  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    Boolean subtract can be thought of as like a bit like process where one solid part is used to eat its way into another, such as a "spark eroding" tool used by toolmakers.

    If you are using the first part solely for this purpose, you would not normally want it to hang around in the model afterwards, but if the "tool" is a functional part (as in the pins in the cantilever clamp in the wonderful Onshape tutorial) then you would choose "Keep tool"
  • allen_stewartallen_stewart Member Posts: 32

    I feel like an idiot but I still don't get it.  Explain it like you would to a 12 year old. 

  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    Part A and Part B are placed with some of Part A inside Part B.
    Boolean subtract makes a hollow in Part B wherever Part A is inside it.

    Part A is called the Tool (and part B the target ?, from memory)

    If that's all you wanted to use Part A for, then don't keep the tool.
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    I'm on a slow connection, and I can't recall the name of the exact clip, so hopefully someone else will post a link to the video showing the modelling of a clamp (like a Kant-Twist cantilever clamp) where the pins are also used as tools to make the holes in the pivot bushes.

    This is a situation where you DO want to "Keep Tool"
  • raino_paananenraino_paananen Member Posts: 17 ✭✭
    edited June 2015
    @allen_stewart ;

    If you locate two solid bodies together in a way that they are interfering each other. You can Subtract the overlapping volume from either one of the bodies to make the two parts fit etc. In this boolean operation one of the bodies is used as a tool to cut from the other part. If you don't tic the keep tools box, the body that you use as a tool will disappear after the operation. If you tic the keep tools box, The same operation will happen but both bodies will be kept in the part studio. Hopefully the pics will help.

  • allen_stewartallen_stewart Member Posts: 32
    I appreciate the info, I hope someone posts the vid.  Im interested to see it in action.
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    edited June 2015
    Looking @raino_paananen 's excellent graphics, a better (and much more ancient) analogy springs to mind.

    Almost the earliest recorded capture of "written" info (I seem to recall) is Sumerian clay tablets, popular 5 millennia ago, where a wedge-profile tool was pressed into the soft clay, to form complex characters with simple wedge shaped elements, called cuneiform (sp?).

    I think the tool was called a "stylus" (not by the Sumerians, but by those who came later)

    The "pages" were highly durable once they were fired in a kiln. I think the style of character had originally started as a form of book-keeping, which Sumerians were obsessed with. (A bit like our four verticals with a diagonal slash to keep a tally)
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