Generative Design - Clear Line of sight

[tom.strudwick]

Hello!

I was wondering if someone would be able to expand upon the 'clear line of sight error' when simulating on Fusion 360 Generative Design please?

My understanding from trial and error is a linear line, between preserve geometries, must be obtained. If this requirement is not met the error occurs, and to combat this effect either alter the drawing to accommodate or use starting geometry. Please see below image detailing a side profile of a bracket, line 1 not accommodating requirement, whilst line 2 does. 

In reference to starting Geometry, how does this then differ to undertaking Topology Optimisation? 

Thank you for your time!

[peter.champneys]

Hi Tom,

The line of site rule is essentially a helpful way to notice that a generative design study may run into a problem where your starting shape is split into two pieces that generative design can't find a way to reconnect by itself. The image you share above is a bit of an edge case where I would actually expect this to be fine without a starting shape most of the time, but putting in a starting shape manually is not a bad idea just to be sure.

All a starting represents is the initial iteration of the generative design study. Unlike topology optimization, this doesn't represent an outer limit to the part, just the first iteration of the shape. Generative design can add and remove material from this first iteration and will often end up with something completely outside of where your starting shape began. It's essentially just a kick off point to help get the algorithm started.

See the image below for an example. You can see a wide variety of starting shapes as inputs in yellow vs the final outcome from generative design

 

[tom.strudwick]

Hi Peter, 

Thank you for your response, this is very helpful. 

I've produced a few attempts, initially without a starting geometry (fig 1), and following with a standard geometry (fig 2). However both ran into errors and unable to produce a GD study.  

I have also attached the file for reference, I was wondering if you would be able to assist please? I'm struggling with this, becoming quite frustrating !

Fig 1 - Left side (Side view) / Right side (Front view)

Fig 2 - Geometry with starting shape (I appreciate this geometry is not suitable for real world, included to generate a connection to preserve geometries). 

I look forward to hearing from you, 

Kind regards, 

Tom.