topic Betreff: Terrible performance of sketch with many simple lines in Fusion Support Forum

Terrible performance of sketch with many simple lines

M_SikorskiH25AT — Sat, 29 Mar 2025 17:49:44 GMT

I am trying to draw very simple object in Fusion and it takes hours to execute any action. I want to prepare model for 3D printing. I need small, thin walls with pattern of wholes repeated on lets assume rectangle 20x30cm. I have drown small, repeatable part of the pattern and then tried to copy it to cover whole element. I cannot do it efficiently, as after selection of houndreds of those elements coping often crashes the Fusion. Finally, after many hours I drawn those sketches by coping only small parts of the drawning (to copy less than 2k of elements). But now I cannot extrude this pattern as Fusion crashes when I select "Profile" in Sketch Pallet, and I think I won't be able to extrude without that.

It is very strange as this pattern is very simple, each whole is just hexagon, so just 6 lines and and 12 point each. But having anything in bigger number causes performance problem. I tested it on M4 Pro and i7 gen 11 with RTX 3080 TI.

How can I improve performance of this operation.

Attached screenshots shows sketch I made, where I cannot extrude drawn elements as Fusion crashes when Profile is selected.

Re: Terrible performance of sketch with many simple lines

jhackney1972 — Sat, 29 Mar 2025 19:18:43 GMT

Please attach your model. If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

Re: Terrible performance of sketch with many simple lines

TheCADWhisperer — Sat, 29 Mar 2025 20:47:11 GMT

@M_SikorskiH25AT

Bottom line - you are modeling incorrectly.

Use computationally efficient techniques and everything will be fine.

Betreff: Terrible performance of sketch with many simple lines

g-andresen — Sat, 29 Mar 2025 21:32:49 GMT

Hi,

1. create just one sketch profile

2. Extrude (cut) this profile

3. Create a rectangular pattern using „feature“ (extrude / cut)

(view in My Videos)

günther

Betreff: Terrible performance of sketch with many simple lines

M_SikorskiH25AT — Sun, 30 Mar 2025 18:58:24 GMT

This is what I need. But still performance of sketch with multiple lines is unacceptable, as I used to make much more complicated drawing in Autocad.

Betreff: Terrible performance of sketch with many simple lines

jeff_strater — Mon, 31 Mar 2025 00:31:48 GMT

AutoCAD is not the same as Fusion. In AutoCAD, you are just drawing lines. There are no constraints and dimensions to solve. Fusion sketches are constrained, so each set of constraints you add will make the solve time slower. The Fusion sketcher is not intended to create large drawings, while that is exactly what AutoCAD was created for. The Fusion sketcher is optimized for creating small sketches that serve as input to a single feature. Apples and oranges...

Betreff: Terrible performance of sketch with many simple lines

TrippyLighting — Mon, 31 Mar 2025 11:47:42 GMT

I'd venture a guess that you did not use a constraint based sketch in AutoCAD, so you're not comparing apples to apples.

If you turn off profile detection, then the sketch will become more performant. Then, of course, you cannot pick profiles for extrusion, but you can turn it back on when the sketch is fully dimensioned and constrained.

If you fully constrain and dimension the sketch, it again will become more performant.

Betreff: Terrible performance of sketch with many simple lines

TheCADWhisperer — Mon, 31 Mar 2025 12:22:59 GMT

@M_SikorskiH25AT wrote:
I used to make much more complicated drawing in Autocad.

@M_SikorskiH25AT

Can you show an example of a Parametric sketch you made in AutoCAD?

Most AutoCAD users are not even aware that they can make Parametric sketches in that software.

The image of your example in AutoCAD should look something like this...

Note the glyphs for the geometry constraints.