Creating a sketch for building a light house made of wood

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
chrisb
Veteran
Posts: 53920
Joined: Tue Mar 17, 2015 9:14 am

Re: Creating a sktech for building a light house made of wood

Post by chrisb »

Are you aware that FreeCAD keeps backup files? However you have to look at the modification times to find out which is the most recent backup file. If you simply have copied the file with the highest or the lowest extension number you probably haven't got the latest state. If I am using new functions - especially in the development version - I like to set the number of backup files to a rather big value, 10 or 15 and I save often. I never had any problems with a saved file.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
derNiwi
Posts: 40
Joined: Thu Oct 22, 2015 7:22 am

Re: Creating a sktech for building a light house made of wood

Post by derNiwi »

Hi, after a long time and several tiny projects with Fusion 360 I'm back to FreeCAD. I've started this project first with FreeCAD, than created the light house again with Fusion, solving some problems and ending with an almost complete project. But now I'm trying to create plans so I can use the saw to cut the parts. Therefore I need almost good data. And this is where I struggled with Fusion. It seems to be good to create 3d models for 3d printers or cnc milling, but the technical plans seems hard to create.

With FreeCAD I started from scratch, still using a spreadsheet and formluas for beeing flexible. But I'm also struggling with the measurement of length and angles. Since I know the angle on the long edge of a side wall from is not the same than the projection on the ground it seems also difficult to measure it. Also the length of the side wall is not identical to the height of the tower.

For the length of the side wall I tried to meause from the top line to the bottom line, also I tried to create a third sketch and use projected points of the upper and lower sketch without success.

For the angles on the long side I need an rectangular cut.

And I like to measure without destroying the file. Of course it might be possible to rotate and move the parts so the fit the XY layer it might solve some issues.

I know that the drawing workbench has been / will be replaced with the TechDraw workbench I'm ot sure if it is easy to use.

Does someone have an idea how I can get the measurements for the outer shape of a side wall (length about 1002,4mm) and the angle of the outer side on the long edge (about 67,6 degrees)? The values were measured with Fusion..

Regards
Nils
Attachments
Lighthouse FreeCAD 001.zip
(25.32 KiB) Downloaded 22 times
User avatar
Shalmeneser
Veteran
Posts: 9474
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Creating a sktech for building a light house made of wood

Post by Shalmeneser »

In TechDraw, you can show isometric (?) view.
And you can show dimensions of the 2D (738.72) or the 3D (1011.19) measurement (TechDraw_Dimension_Link).
The angle is in 2D measurement, so certainly wrong for real measure.

There is also a macro (FCCamera ?) to show a face parallel to the screen, so in that case 2D=3D.

btw, FCstd = zip !
Attachments
Cordouan.png
Cordouan.png (238.88 KiB) Viewed 1059 times
Cordouan.FCStd
(31.19 KiB) Downloaded 15 times
chrisb
Veteran
Posts: 53920
Joined: Tue Mar 17, 2015 9:14 am

Re: Creating a sktech for building a light house made of wood

Post by chrisb »

Shalmeneser wrote: Fri Jul 30, 2021 9:12 pm btw, FCstd = zip !
Indeed! If you want improved compression, increase the compression level of FreeCAD file.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
User avatar
thomas-neemann
Veteran
Posts: 11801
Joined: Wed Jan 22, 2020 6:03 pm
Location: Osnabrück DE 🇩🇪
Contact:

Re: Creating a sktech for building a light house made of wood

Post by thomas-neemann »

derNiwi wrote: Fri Jul 30, 2021 8:17 pm ...Does someone have an idea how I can get the measurements...
hallo nils

this is my way: (manipulator)

https://www.youtube.com/watch?v=UUl1uk0_-r4

phpBB [video]


Greetings Thomas
Gruß Dipl.-Ing. (FH) Thomas Neemann

https://www.youtube.com/@thomasneemann5 ... ry=freecad
derNiwi
Posts: 40
Joined: Thu Oct 22, 2015 7:22 am

Re: Creating a sketch for building a light house made of wood

Post by derNiwi »

Hi,

@Shalmeneser: yes, this is exactly the problem, just a projection does not give the right angles. The 67.50° is the same as the calculated value for the angle in the octagon. But I need the angle on the long side of a wall which is due to the double miter cut 67,71° (calculated).

@Thomas: the Manipulator workbench is very helpful. It gives me 112,39° which is the outer angle. If I calculate 180° - 112,39° = 67,71° the result is ok.

However, for using the TechDraw workbench it seems I have to create multiple views for the measurement in this trapezoid. Since I created the side wall with two sketches and a loft between them maybe this is not usable for a view. Also it seems not directly (without add ons) posible to measure the distance between the bottom and top edge of the side wall.

Maybe the creation of the side wall is not the best way for this project, but currently the only one I could figure out and beeing flexible.

But as I said, the values from the manipulator seems to be fine I can live with that.

Thanks
Nils
User avatar
Shalmeneser
Veteran
Posts: 9474
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Creating a sketch for building a light house made of wood

Post by Shalmeneser »

derNiwi wrote: Sun Aug 01, 2021 4:56 pmBut I need the angle on the long side of a wall which is due to the double miter cut 67,71° (calculated).
Sorry, but TechDraw doesn't want to give me the right angle in the isometric view (it gives me 0°).

Is there anybody that can work better with TechDraw ?
What's the name of the macro to set a face parallel to the screen ?
derNiwi
Posts: 40
Joined: Thu Oct 22, 2015 7:22 am

Re: Creating a sketch for building a light house made of wood

Post by derNiwi »

It is not only to set the face parallel to the surface, but this is necessary for getting the real length. I think I need a second view perpendicular to the long edge through the side wall. And also two other for the both short edges (which in this case should result in equal angles). A fourth view for the other long side will not be parallel to the first one…

I think for making TechDraw much more easier to use is having a function implemented where the parallel facing of one flat side could be easily done. Also the measurement should not just use the projection… I‘ll try to find out if someone have requested this…
User avatar
papyblaise
Veteran
Posts: 7870
Joined: Thu Jun 13, 2019 4:28 pm
Location: France

Re: Creating a sketch for building a light house made of wood

Post by papyblaise »

a little descriptive geometry: one wall is perpendicular to the XZ plane so its real height is in this plane, but I will also be able to use it to know its inclination
so I do a sketch in XZ in Referance at the edge, I know its angle (7.89)
I make a clone of it that I straighten by 7.89 °
a projection in Techdraw and I don't need a Macro, although it is useful in more complex cases
Attachments
planche.FCStd
(31.75 KiB) Downloaded 16 times
planche.PNG
planche.PNG (8.98 KiB) Viewed 854 times
planche2.PNG
planche2.PNG (15.31 KiB) Viewed 854 times
derNiwi
Posts: 40
Joined: Thu Oct 22, 2015 7:22 am

Re: Creating a sketch for building a light house made of wood

Post by derNiwi »

So your recommendation is to clone the main side wall, create a perpedicular sketch and align the clone to a default view?

But one mistake is the angle of 67,31° This is because you get this value of an projection in this view direction. The clone have to be rotated that the long edge is aligend to a base axis, just for this side view.

I'm currently trying to create a view which I can use for TechDraw but I'm currently not successful. My idea for a macro is to do this:
  • one (flat) face has to be selected
  • the macro will loop through all the used edges
  • the center of the edge / line has to be calculated
    • a view perpendicular to the edge and one direction parallel to the selected face will be created
    • an element on a TechDraw page will be created for this view
Post Reply