Cannot select line on datum plane

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ArnoldGoat
Posts: 10
Joined: Tue Jan 25, 2022 2:47 am
Location: New Zealand

Cannot select line on datum plane

Post by ArnoldGoat »

Hi
I am new to FreeCAD. I am trying to model an octagonal timber roof frame so I can replace the roof on my gazebo.
I have modelled the rafters (hips) OK, but I need to place noggins (dwangs) in between the rafters. I have created a datum plane spanning the insde edges of 2 adjacent rafters in Part Designer WB, but when I try to create a sketch of the noggin, I can draw the piece on the plane, but I can't select the rafter edges so I can constrain the sketch to them. I hope someone can tell me what has to be done. I am attaching my current file. Apologies if this has already been covered, but I couldn't find anything. TIA.

Ken


OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: English/New Zealand (en_NZ)
Attachments
roof.FCStd
(59.33 KiB) Downloaded 16 times
chrisb
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Posts: 53928
Joined: Tue Mar 17, 2015 9:14 am

Re: Cannot select line on datum plane

Post by chrisb »

In the preferences you have enabled to enter SectionView as soon as you edit a sketch. You can switch it off when in Sketcher, or you may consider to set MapReversed=True and edit the sketch from the other side.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
ArnoldGoat
Posts: 10
Joined: Tue Jan 25, 2022 2:47 am
Location: New Zealand

Re: Cannot select line on datum plane

Post by ArnoldGoat »

Thanks for your answer, but I am still having problem. I reworked it a bit, so that the rafters are an array in draft rather than in part design as they are separate solids.

I still can't select the edges that form the datum plane as constraints for the noggins. I've tried selecting and deselecting the sectionview toggle.

I have a feeling that I should have asked: "how would you go about modelling a set of 8 rafters for an octagonal pitched roof, with horizontal noggins half way up". Then I might not be in such a mess!

OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: English/New Zealand (en_NZ)
TheMarkster
Veteran
Posts: 5505
Joined: Thu Apr 05, 2018 1:53 am

Re: Cannot select line on datum plane

Post by TheMarkster »

I don't really understand the question. Perhaps you can use links to external geometry to do what you are trying to do.
Snip macro screenshot-11632c.png
Snip macro screenshot-11632c.png (109.65 KiB) Viewed 869 times
If the link is to something outside the body, make a shapebinder of it first, then get external links to the binder.
ArnoldGoat
Posts: 10
Joined: Tue Jan 25, 2022 2:47 am
Location: New Zealand

Re: Cannot select line on datum plane, tech draw advice pse.

Post by ArnoldGoat »

Thanks for the suggestions. I have proceeded reasonably well now and with a bit of slicing have got the 4 different different timber pieces modelled in 3D. I now need to do TechDrawing so that I can show the angles and dimensions of the cuts.

The hip rafter is easy enough as there was a view normal to the plane. The others are more difficult.

Can someone tell me how to do 2 views of the noggins, one of the top to show the main bevel, and the other from the end to show the other angle. I know the mitre saw can do it in one go, but I need to determine the angles. I have "DatumPlane" which is the top surface of both noggins; can I use this to specify the tech drawing view?

OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: English/New Zealand (en_NZ)


Ken.
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