topic Re: A shape that is impossible to draw in Fusion360 in Fusion Design, Validate & Document Forum

A shape that is impossible to draw in Fusion360

saulius1005 — Thu, 30 Jan 2025 18:00:43 GMT

I'm trying to draw a hole of this shape in a cylinder, but it looks like creating such a 3D shape will take at least half a day. I tried both spline options, conic curve, and arc.

With the fitpoint spline, it almost works, but in that case, the front shape doesn't come out right, and the circle becomes not quite round.

Re: A shape that is impossible to draw in Fusion360

TrippyLighting — Thu, 30 Jan 2025 19:22:17 GMT

Dead easy!

Re: A shape that is impossible to draw in Fusion360

saulius1005 — Thu, 30 Jan 2025 20:20:30 GMT

How did you do that? Wait, it’s not working for you either.

Re: A shape that is impossible to draw in Fusion360

TrippyLighting — Thu, 30 Jan 2025 20:16:45 GMT

If you download the design file I had attached to my message, you can roll it back all the way to the beginning and then forward step by step.

That explains how the design was constructed.

I can create a screencast if you still have questions.

Re: A shape that is impossible to draw in Fusion360

TrippyLighting — Thu, 30 Jan 2025 20:37:10 GMT

If you edit the sketch and reduce the angle, what do you observe?

Also, the geometry in your sketch is impausible and does not reflect the actual physical part.

The views in your sketch contradict each other!

Re: A shape that is impossible to draw in Fusion360

saulius1005 — Thu, 30 Jan 2025 20:41:30 GMT

Here’s what I mean. If I use a spline, everything has to be done manually. That is, each point needs to be moved along the XYZ axes until it somewhat resembles an arc or a circle (depending on the viewing angle—top, side, or front). But maybe there's a way to ensure that a circle stays a circle, an arc stays an arc, and the front view is a perfect 90-degree angle instead of something that just roughly resembles these shapes, like it does now.

Re: A shape that is impossible to draw in Fusion360

saulius1005 — Thu, 30 Jan 2025 21:07:25 GMT

Here is the real part and its view from the top, side, and front.topfrontside

In reality, forming this part took 1 minute in the Fusion program...

Re: A shape that is impossible to draw in Fusion360

KristianLaholm — Thu, 30 Jan 2025 21:32:47 GMT

This is what I see in your design intent.
The Front and Side view in your drawing doesn't add up for me, one of them feel rotated.

Re: A shape that is impossible to draw in Fusion360

TrippyLighting — Thu, 30 Jan 2025 23:47:52 GMT

Spot on. That little radius the OP left out of his simplified paper/pencil sketch makes all the difference.

Betreff: A shape that is impossible to draw in Fusion360

g-andresen — Fri, 31 Jan 2025 10:09:02 GMT

Hi,

This is how I would do it

(view in My Videos)

günther

Betreff: A shape that is impossible to draw in Fusion360

saulius1005 — Fri, 31 Jan 2025 12:12:02 GMT

Thank you all for your help! I finally managed to draw this shape! Thanks again!