Generative Design Inquiry

[tranq006]

Hello,

Let me preface by saying I have no experience with generative design. However, I'm trying to get rid of unnecessary material on a simple bracket, and while I thought I set up the steps correctly, am not getting the results I had hoped for. Please see screencast in link.

Additionally, if anyone has experience with Meshmixer, that could help as well. I could easily achieve what I am trying to do with a simple pattern feature, but need a way to preserve the material around the screw locations which I was also unable to figure out in Meshmixer. Thanks for the help.

[I_Forge_KC]

Your screencast didn't seem to attach.

[tranq006]

I changed it to public. Should show up now. For some reason audio wasn't coming through. If you need me to re-record to understand my question please just let me know. Thanks

https://autode.sk/2X1p7ri

[Ben-Weiss]

Hello tranq006!

I took a look at your screencast, and after attempting to fill in the details from your missing audio, it seems like the preserve bodies around the bolt holes aren't showing up in the outcomes that were generated. At least I expected to see the features drawn in green in the outcome you showed:

Was that the issue? If so, see below; if not, please let us know!

The lack of those preserve bodies seems like an error on our end. Can you switch the view to Model View when you're looking at the outcome and tell me if the rings re-appear?

 If you don't mind uploading the Fusion document (File->Export->Type = Autodesk Fusion 360 Archive Files), I'd like to take a look.

Alternately, I'm happy to help you through lightening the part with a pattern that avoids areas around the holes, and I have some experience with Meshmixer lattices as well.

Thanks,

Ben

[tranq006]

Hello Ben,

Sorry for the late reply, I didn't see another email. Yes what you described is the issue. I have attached the Fusion file here. If you are willing to help figure out a pattern in those areas, that would be great! I of course could do a simple pattern in Fusion, but was trying to get a more aesthetically neat looking pattern such as what you can do in Meshmixer. Let me know how you would like to proceed.

Thanks

[Ben-Weiss]

Hi @tranq006 ,

Thanks for the upload! I re-ran your generative setup, and for me the preserve bodies are retained in the final design. I don't know why they didn't show up for you.

If this continues to happen for you, let me know and I'll investigate further. I have attached the export for this result.

Looking at your generative setup, there are a few things I would suggest, given that you're looking for a "aesthetically neat, lightweight" shape. Generative design works best when you have some physical information about the loads your part will experience, as well as information about the material(s) and manufacturing methods you might want to use. Since we don't have any of this information, I made some tweaks to try to get an interesting outcome anyway.

• I picked unrestricted as well as 3- and 5- axis milling configurations. Additive results tend to be a bit ugly, so I turned those off. The milling configurations will not remove material from the interior faces of your starting shape because they cannot be reached by the tool. I'm assuming you're not going to actually machine these parts, so I set the tool shoulder length to a relatively small number (1 mm more than the tool diameter), as this speeds up the generation process.
• I picked a handful of materials instead of just one (I chose a few different alloys of Aluminum). This increases the number of designs you get to sort through and avoids cases where all of the generated geometry is too thick or too thin for your purposes.
• In the file you uploaded, the 1N load was on the top face of the plate and the constraint was on the bottom face of the same plate. This isn't enough load to stimulate generative to do much of anything with your part (except shrink it uniformly). I added a few loads to the top preserve body and to the bolt holes to try to encourage material to be created connecting the loaded pieces with the support plate. For an aluminum part of this size, 1N is a tiny load. Try 1000N.

With those changes, I re-ran your study and came up with some alternative solutions. Three of the 30 or so generated outcomes looked interesting to me.

Typically, I would look at these results and then make some changes to my loads to try adjust the amount of material in different regions of the design and re-generate until I had something I liked. You could also try a starting shape with some holes patterned into it; that would give you a more lattice-like outcome instead of a sheet.

Fusion Pattern Solution

For a Fusion pattern, I'm not a designer, so I don't have much skill at making Fusion do aesthetically pleasing things. What you can do, though, is create a rectangular pattern of holes (or other geometry) and then suppress the instances that overlap with your mounting bodies. I wouldn't call it pretty, but it achieves the goal of not punching holes where your bolts need to attach.

If you'd like help making a prettier pattern, you might reach out with a different forum post and get input from others more skilled than me!

MeshMixer Solution

For the MeshMixer lattice, I exported the bodies used in your generative setup as STL and pulled them into MeshMixer. I used the Edit->Make Pattern command to generate the lattice, using a gradient to cause the regions near the support brackets to be thicker.

I brought the STL for the lattice back into Fusion, decimated it, converted it to a brep, and combined it with the preserve and obstacle bodies to produce a final design.

If you want to follow along this process, I can create a Screencast for you...it was pretty trial-and-error for me the first time.

I uploaded your design with all three approaches included (revised generative setup, Fusion pattern, and MeshMixer lattice).

Hopefully that helped answer your question!

Ben

[tranq006]

Hello @Ben-Weiss 

Thank you so much for the informative response! I am glad to see that it did in fact preserve the geometry when you re-ran it - it must have been an oddity on my side. 

Some of the results in your new generative design look promising, but I will probably look towards patterning in Fusion or Meshmixer as in the end I am looking to get all 8 brackets somewhat similar looking, which will be difficult to do with the generative design. 

For the Meshmixer result, what you did is very promising. I did not do anything with the gradient feature which looks like is what helped preserve the material around the screws. If you wouldn't mind attaching a screencast, that would be great. Just to note, I will need material removed for the counterbore for the screw. Do you think it is also worth following up with a post regarding how to do patterns similar to what was achieved in Meshmixer using Fusion?

Thanks again.

[TrippyLighting]

@Ben-Weiss could you post the un-decimated Meshmixer mesh/result for that pattern?

This would be an interesting object to re-mesh with Remake, or my favorite free tool InstantMeshes. It would avoid having to use a highly faceted, but still crappy looking BRep 😉

[Ben-Weiss · Accepted solution]

Hi @TrippyLighting and @tranq006 ,

I put together a short screencast that covers exporting the design from Fusion and creating the lattice in MeshMixer: https://autode.sk/349QvFd

The STL is attached. Since converting the mesh back to a B-rep really isn't my area of expertise and I fumbled my way through it previously, @TrippyLighting could you walk us through a better method to create a brep from this?

Once I had a brep, all I had to do was Combine/Union with the top and bottom plates as well as the preserves, then Combine/Subtract the obstacles.

As far as building this kind of lattice natively inside of Fusion, I'm not aware of any easy way to do it, short of finding or making an add-in. We have plans to support for some better lattice generation and manipulation tools inside of Fusion, but they are still in development.

Ben