How do I create an ellipse in an Isometric Projection ...

I tried to design an ellipse with QCAD Tools - but I stuck … maybe someone has an easy solution for me :sunglasses:

Case: Imagine a model wall build with round dowels - like a Blockhouse,
Now I have to cut the top round dowels under 30° to get a gable shape,
In an isometric this cut has to appear like an ellipse on both sides,
Right side was easy to do with QCAD - maybe not absolutely correct but good enough :wink:
Left side … a disaster :laughing: I have no idea how I can make it correct looking :blush:


A square dowel shape is used as the construction base in the isometric.

I know how to design a correct ellipse step by step - that is not what I’m looking for! I’m looking for a fast and “just good enough looking” solution in QCAD!
Any Ideas? :open_mouth:
Iso Ellipse.dxf (86.6 KB)

Hi Husky
Do you mean something like this ?

YES! Nice!!! How??? :open_mouth: I’m to dummzumzum! :laughing:

Well, ideally we need some additional options in the ellipse tools to produce something like this easily!

So… for me I didn’t use the ellipse tool, I instead used the Spline (control points - sp) tool, which to be honest with an ‘oblique’ rectangle as you have here, is a lot easier to achieve something that resembles an elliptical shape.

This is how I done it - it’s not straight forward but it does get the job done for now.
1.First make a grid.
2.Use the Spline tool (control points) and fit to the grid intersections.
3.Copy and paste the rest where you need them.

Nice, thanks a lot! The grid was the trick :wink:


Yep - that would be nice! But I’m sure - we have just to sit tight … :sunglasses:

And here it is! :laughing: :laughing: :laughing:

The new QCAD update - 3.2.1 - has a new tool what solves problems like this with just a few mouse-clicks. Perfect!!!

The new tool is called:
“Ellipse: Inscribed in quadrilateral (tangential to four lines) (EQ)”
Husky-2013.08.16-07.png
You have to try it by yourself! :sunglasses:

’ Yippe kay yay’ :smiley: :smiley: :smiley: :sunglasses:
Yes what an excellant tool, I’ve been playing around with it…so very useful, especially for isometric work :wink:
Have you also noticed the extra Circle ‘geometry’ tools:
Main menu > Misc > Drawing…

Yes I have - but the absolute winner for me is:
Modification tools: Clip selection to rectangular area.


Be a little creative, play in combination with this tool also with the clipboard and you can see how powerful this tool is!!! :sunglasses: