2d constraints for finger joints

I want to create finger joints on a single piece with a variable number of "fingers". I have the parameter nof (number of fingers) but can't come up a workable method. Any ideas on how to achieve this with 2d constraints?
thanks!

Comments

  • Because you are posting your question in the Mech forum:
    Are you aware that creating a constrained 2D sketch as the basis for a 3D model doesn't make sense in BricsCAD? In BC you create your 3D model and then apply 3D constraints. You can, and often will, use 2D elements while creating a 3D model, but the model will not be linked to these elements.

  • Yes of course - I wasn't thinking. No parent child dependencies in BC.
    So I still have the problem: If I model finger joints and apply 3d constraints, how can I create a component where the number of fingers is controlled by a parameter?
    thanks

  • Maybe fingers are array of boxes subtracted from the board.

  • @CADMebel said:
    Maybe fingers are array of boxes subtracted from the board.

    See model and movie in attachment.
    Parameters are:
    n: number of fingers
    OW : overall width
    FL: length of fingers

  • Thanks for getting back - yes this works for me. So I'll do the same for the mating pieces but offset the width of the finger.
    cheers

  • To create the mating piece, explode the block, then subtract the resulting solid from the mating piece. See movie.

  • Ian Johnson
    edited January 2020

    @Louis Verdonck said:

    @CADMebel said:
    Maybe fingers are array of boxes subtracted from the board.

    See model and movie in attachment.
    Parameters are:
    n: number of fingers
    OW : overall width
    FL: length of fingers

    Louis, that is a very good demo of how parameters work.

    Where can we find some tutorials on how to create similar sort parametric blocks (using arrays) and then subsequent BIM details?

    thx

  • I've been working with this method for a while and have hit a road block. When you decrease the width of the part, it fails (see attached video.)
    I've also attached my own version showing an array on 4 corners that fails as well but not sure why. Looking for ideas otherwise I'm stuck.

  • Hi Scott
    When you decrease the width with more than the twice the width of one finger, the problem occurs. So when reducing the width either keep the value below 2*finger width or temporarily reduce the number of fingers.

  • Obviously you will need to reduce the width in more than one step ...

  • I can work with that, thanks. Here is another weird issue I'm having but based on your suggestion, I lower the number of fingers to 1 and it disappears. (see video)
    When I change the depth of the box sides, the back end falls apart. But if I change the fingers to 1, then make the change, it's good. Then I change the finger count back to what I want. I think it might have to do with the Depth distance constraint being tied to the back edge of the side. When the fingers are changed, the constraint is tied only to the lower finger so all the rest go elsewhere. I'd like to come up with a solution so this doesn't happen. Thoughts?

  • Hi Scott
    To automatically handle the issue shown in your movie, programming is needed. Kind of a 'if ... then' clause. I'm not a programmer, I can only point you in the right direction using default commands and some 'tips and tricks'.

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