2D problems. Large pattern chokes Fusion 360. Is it the wrong tool for this?

[lens42]

I'm trying to lay out a 2D design - Something like a circuit board. I have made a small "cell" that I want to make into a 100x100 array. When I try to make a 100x100 rectangular pattern of the cell in the sketch, Fusion360 grinds to a halt. I have tested smaller arrays and I can see it get slower and slower as I try large grids. My cell is pretty simple, So I wouldn't expect fusion to choke on a 100x100 grid of these. There is no 3D content. In the end I'd like a dxf of the array that I can give to a fab house. Am I going about this in the wrong way?

My PC is a pretty new LG laptop: Intel Core i7-7550U 2.9GHz, 8GB RAM, 64 bit, Intel HD Graphics 620, Samsung SSD. It has worked fine for any 3D stuff I have done, but none if it was complex - mostly parts for machining with no moving pieces.

[jeff_strater]

Yes, you don't want to do this in a sketch.  It is much faster to do this as a feature pattern (extrude your cell and pattern that).  However, 100x100 will be very slow even as a feature pattern.  That is true for any CAD system, it is not just Fusion.  That is a lot of compute to be done.  So be prepared to wait a lot.  Then, you could export the result by sketching on the top face, and extracting a DXF from that.  However, expect that to be slow, too.  

Sorry not to have better news for you

[lens42]

Thanks, that did help, but not much. When you say "slow", I assume that is not code for "lock-up", because lock-up is what happens for any array larger than 8x8. I'm not sure how long it should take, but I get "fusion 360 is not responding". Also I pulled my sketch of a single cell (shown in picture in my original post) into a solid and tried to start another sketch on the surface (for other features), but even that locks up. It freezes when I try to select the plane for the new sketch. I've been using Fusion 360 for other simple modeling without too many issues and don't really see how this is any more complex (at least when dealing with a single cell) than what I've been doing before, except for one thing. For the first time I defined user parameters in the "modify" tab so that I can adjust finger size and length without redrawing. That works nicely for adjustments, but could that be choking my PC? If it helps here is the graphic diagnostic info:

[GPU Information]
GPU Device: Intel(R) HD Graphics 620
GPU RAM: 128 MB (Integrated card)
GPU Driver API: DirectX 9.0
GPU Driver Version: 21.20.16.4534
GPU Driver Date: Unknown

[Graphics Effects Settings]
Anti Aliasing: Off
Ambient Occlusion: Off
Object Shadow: Off
Ground Shadow: Off
Ground Reflection: Off
Selection Display Style: Simple
Transparency Effect: Better Performance

[Limit effects to optimize performance]
On

[jeff_strater]

Can you share your model?  I'd like to take a look at it.  When you say 8x8 is slow, is that for a sketch pattern or a feature pattern?  Because a feature pattern should be OK at that level.  I still think 100x100 is just not going to be possible, no matter what CAD product you are using.

Also, understand how operating systems work.  Just because the OS says that a process is "not responding", it doesn't know whether the process is stuck in an infinite loop, is just busy, or is crashing, only that it is not responding to its polling.  You will also get that for a process that is just very busy working, and sometimes if you wait, it will come back and be fine.  I've found often that Fusion will show that status for a while, and recover after a while.

[lens42]

Here's a link to the model:

http://a360.co/2yt5DQO

In it I've made a 4x4 pattern, which is about as large as I can go before things bog down. Feel free to change anything.

I'm a bit confused by your recommendation to make a "feature" pattern. I don't seem to be able to do that. I can either pattern within the sketch (not recommended as you say), or I can pattern a body made from extruding the sketch. That is was is in the attached link. I don't seem to be able to pattern anything else.

I'm still a bit surprised by the pattern limitation, even at 100x100, for a simple geometry it seems like it would be far less complex than the intricate assemblies I see in some Fusion 360 examples, but then I have no idea what's under the hood or why something is easy or hard inside CAD. I know *somewhere* patterns like this are made (with millions of reps actually), but I don't know what tools are used.

Maybe I should be copy/pasting instead? Does that lighten the load? It's less desirable from a modification standpoint, but if it works.....

[jeff_strater]

Thanks for the model.  You've modeled this like I was recommending.  By "Feature Pattern", was just referring to doing the pattern in the Model environment, as opposed to the Sketch environment.  It was not clear to me whether the cells involved overlapped or not.  Because they are not overlapping, your selection of Body as the pattern object type was the only choice.  If, instead, you are patterning, say, extrudes on a common base, then the pattern would be a feature pattern instead of a body pattern.

I played around with your design a bit.  I was able to edit the pattern to be 20x20.  The compute took about 30 seconds to compute, which is about what I expect, and pretty in line with other CAD products.  Once the pattern is computed, the graphics performance (rotating, zooming) was also pretty acceptable.  But, 100x100 is still going to be very painful no matter what CAD program you use.  And, especially if you want to ultimately make a DXF out of this.  

I'm not sure what systems might handle this better.  Certainly some video game systems are capable of handing large amounts of graphics data efficiently, but a video game scene and a CAD model are worlds apart in terms of accuracy needed, etc.

If your only goal is DXF to a fab shop, then I might consider AutoCAD for this.  I'm not an ACAD user, so I can't help you with how to do this, or what kind of performance to expect with ACAD, but it's worth looking into.

[lens42]

Thanks for the work on this. At least it is good to know that I am not using an entirely wrong approach.

[lens42]

Just to close this, I found a solution with another CAD tool called OpenSCAD. I'm not trying to dump on Fusion, since I use it a lot (and will continue to) and love the CAM features, but for simple repetitive geometries, OpenSCAD seems much more at ease. It also has good parametric capability via variables. The downside is It has a very dry command-line interface, but it's not complicated and seems very fast. My 100x100 array that killed Fusion, takes 7 seconds in OpenSCAD. 

[matt]

It's not just 2d patterns. Fusion 360 can't even combine my Boolean request using 50 identical coil patterns. It just chokes. And I'm on a high end PC with AMD threadripper and 32 cores, 64GB of RAM, and the latest update as of 12/7/24.  Really pathetic performance, IMO. Can't even handle making a knurling pattern on a tube. Now I have to export a .step file just to do the pattern in Plasticity, and then reimport. Why is Fusion so terrible with large instances of patterns or booleans?

Really disappointing.