Rationale behind support face requirement for pocket?

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j-dowsett
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Rationale behind support face requirement for pocket?

Post by j-dowsett »

Wondering if someone can explain the reasoning behind requiring a support face for a pocket? I'm simply trying to better understand the philosophy of FreeCAD, hopefully to make it's use more instinctive to me.

I've had a few occasions where no support face exists and it's necessary to create a pad and do a boolean cut. Is this an intended/accepted consequence, or am I missing an alternative solution?

This screenshot provides a simple illustration:

Image

I've noticed that pads have a 'Mirrored extent' property, I assume this has not been implemented yet?
wmayer
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Re: Rationale behind support face requirement for pocket?

Post by wmayer »

Wondering if someone can explain the reasoning behind requiring a support face for a pocket? I'm simply trying to better understand the philosophy of FreeCAD, hopefully to make it's use more instinctive to me.
A pocket is a hollow i.e. it removes some material from another solid which is done with boolean cut operation. But you can't do a cut with "nothing".
I've had a few occasions where no support face exists and it's necessary to create a pad and do a boolean cut. Is this an intended/accepted consequence, or am I missing an alternative solution?
As shown in you screenshot that's the way to go. A pocket always needs a plane as face and thus doesn't work with cylinders or other surfaces.
I've noticed that pads have a 'Mirrored extent' property, I assume this has not been implemented yet?
AFAIK it's not implemented.
j-dowsett
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Re: Rationale behind support face requirement for pocket?

Post by j-dowsett »

Thanks. Just making sure I wasn't missing something.

Thinking about it the behaviour is the same as I'm used to, just that the make-pad, boolean-cut steps were hidden/combined into one 'extrude as cut' step.
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jriegel
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Re: Rationale behind support face requirement for pocket?

Post by jriegel »

Actually the pocket is at the moment really done for imprints on planar faces. for your use case I would do a different feature.
You can do this by adding the support by hand...
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NormandC
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Re: Rationale behind support face requirement for pocket?

Post by NormandC »

jriegel wrote:Actually the pocket is at the moment really done for imprints on planar faces. for your use case I would do a different feature.
You can do this by adding the support by hand...
Out of curiosity, do you plan for the Pocket feature to eventually be able to handle a case like j-dowsett's?
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jriegel
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Re: Rationale behind support face requirement for pocket?

Post by jriegel »

Sure! the problem at the moment is we can not automatically find the support. We need the MainPart (Main Body) feature for that.
Stop whining - start coding!
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