Best Known Method for attaching a sketch/part?

[tonydiethelm2]

I can do this the stupid way. Already have.... . I'm looking for the Best Known Method here....

It's a Ukelele, to be machined by a CNC from the back.

I need to attach the headstock. I can't just design it and jam it on there. I need distances to be correct.

The neck placement is controlled by the offsets of the heel and nut sketches. That has to be correctly placed or it messes up my bridge placement.

How do I attach the headstock sketch to the neck? Ideally, I'd want to use a constraint and fix the ends of the neck onto the lower curve of the head piece.

I can design the headstock and just use boolean addition to "jam it on there", but that's not precisely placed.

I could design the headstock sketch at the origin and use the attachment offsets or Sketch Reorient tool to place it correctly... but that's a PITA with that curve. I don't know the vertical length of the sketch easily. And I don't know if that's the "BKM".

Can I attach my sketch to the NeckNut sketch in another plane? That'd work great.

I can.... go into construction mode and create a line on the edge of the neck piece, then constraint my sketch onto that?

I need the placement of my sketch to be dependent on an already created part. What's the GOOD way to do this? I know it's done.

Thanks in advance.

OS: Ubuntu 18.04.2 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13541 (Git)
Build type: Release
Branch: releases/FreeCAD-0-17
Hash: 9948ee4f1570df9216862a79705afb367b2c6ffb
Python version: 2.7.15rc1
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

[pl7i92LCNC]

you canuse sketcher to place your sketch
you can externaly use like QCAD or librecad to place your sketch to the origin

and reimport the DXF

the CNC Headstock can be placed oin PATH
like quick guide here

phpBB [video]

[meme2704]

Hi
you tie the sketch of the head below the handle, and you use the tool of creation of referance (blue cube) on the upper arete of the handle which will become violet, this creates to you 1 line and 2 points of reference

[openBrain]

The more stable solution is probably to use some position properties of the nut sketch as a dimension.
As an example, you can constrain the lefter point of the headstock slot with expressions such as "NeckNut.Placement.Base.y" or "NeckNut.AttachmentOffset.Base.z".

[kisolre]

Is it very hard to install and try 0.18 on your system? Your sketches contain redundant constraints (0.18 will show that), there are tons of bug fixes and improvements.
Why is the neck sketch outside of the Body? Is it intended to be a separate body to be glued later? You already gave it a distance in the spreadsheet. Is this correct or just a test?
As meme2704 explained import the edge of the neck into the head sketch, constraint point of edge to the arc and voila:

Ukulele.JPG (165.97 KiB) Viewed 1540 times

Here is a file with what I understand you are trying to achieve (also fixed constraints in neck sketches):

Ukulele_head.JPG (76.38 KiB) Viewed 1540 times

Sketch "Headstockoutside" should be attached to Body.XY_Plane but works that way too.

[meme2704]

Sketch "Headstockoutside" should be attached to Body.XY_Plane but works that way too.

Yes, indid it works too

[meme2704]

As meme2704 explained

many thanks to confirm : I m'not a troll at all

[tonydiethelm2]

you tie the sketch of the head below the handle, and you use the tool of creation of referance (blue cube) on the upper arete of the handle which will become violet, this creates to you 1 line and 2 points of reference

Thank you!!!

Why is the neck sketch outside of the Body? Is it intended to be a separate body to be glued later? You already gave it a distance in the spreadsheet. Is this correct or just a test?

Ah.... Can we speak about that? The neck sketch was made by lofting between two carefully offset sketches to get my scale length correct. I was going to boolean add everything together at the end, then cram the whole thing into PATH for CNC work.

If there's a better way, please do tell.

I'm finding that I can do stuff, but I very frequently find myself wondering if there's a Best Known Method for stuff. I not so secretly wonder if I'm doing everything the kludgy hard way. :/

[kisolre]

Ah.... Can we speak about that? The neck sketch was made by lofting between two carefully offset sketches to get my scale length correct. I was going to boolean add everything together at the end, then cram the whole thing into PATH for CNC work.

If there's a better way, please do tell.

So you want a single solid? Didn't you understand my last post? In the screenshot you can see that the Head is now a feature in the body so that "add everything together" is part of creating the Body. The file in my post is just that - Sketch dragged in to Body, external geometry referenced in sketch (whict is now Ok since sketch is inside body), constraints added to adjust sketch to fit neck, sketch padded and expression added to pad.lenght to adjust to NeckEnd thickness. It is all in the attached FCStd.

[bejant]

you use the tool of creation of referance (blue cube) on the upper arete of the handle which will become violet

Link To External Geometry (the magenta line segment) works but makes the model very fragile, meaning that changing something earlier in the model will probably mess up that Sketch (along with and everything afterwards). The method by openBrain is more resilient to later changes.

Why is the neck sketch outside of the Body?

Isn't Headstockoutside the Sketch that is outside the Body?

tonydiethelm2, we need to know if that is intentional or not (I'm guessing unintentional).