New Custom Feature: Simplify

NeilCooke

A common requirement when sharing CAD data is to simplify it by removing internal details and intellectual property. This feature, in combination with in-context modelling, creates a simplified representation of an assembly or part. Please try it out and if you find any problems or have any examples where it doesn't work, let me know. Enjoy!

https://cad.onshape.com/documents/3f84343841cb6d7fead072c8

Video on how to use:

https://onshape.wistia.com/medias/brqf5bhnb4

Axel_Kollmenter

This is awesome! Thanks!
+1

wayne_sauder

@NeilCooke
Seems like the document is view only. 

john_mcclary

Nice

NeilCooke

wayne_sauder said:

@NeilCooke
Seems like the document is view only. 

It's public - probably the easiest way to add it is to go to the "add custom features" button and copy/paste that URL into the search dialog.

wayne_sauder

Sorry, I was looking in the wrong tab. 

MichaelPascoe

!!

EvanReese

Really cool feature! Thanks, Neil.

imants_smidchens

nice! Beat me to it

+1 really cool

王振翊

這個功能太棒了

fnxf

Great feature! I‘ve missed this, and it will save me a lot of time. 

glen_dewsbury

Thanks Neil. Simplified is a great tool. Think I found an other use for it. "Weldments".
Weldments are made from assemblies but when completed are one part that can be modified. ie. machine the top off to flatten and remove distortion. Drill a few holes and what not.
Would apply to castings also.
https://cad.onshape.com/documents/4d54c097f06df74ad7d2c098/w/95756f907817bad134521b92/e/4e1b749797af37864c6f3b15

stephen_des_jardins

I'm trying to use simplify to build a pipeline from complex onshape to usable urdf for robot simulations. also using onshape-to-robot. It would be great if there was a button to transfer mass and cog (as a custom material density) into the simplify part. Is there a way to find out what/where the "nonmanifold part" error is so it can be fixed or worked around. 

NeilCooke

@stephen_des_jardins - the transfer of mass/CofG is a great idea, however there is no way to read the materials of each part so the only way this could be implemented is by assuming that all parts have the same material (unlikely). You might have to do this manually by noting down the values in the mass props dialog and adding them to the simplified part.

Any non-manifold error is where two parts are touching at an infinitely small edge or vertex, so you may need to modify or move/remove one of the parts (full disclosure - I cheated in the video - the shaft seal on the gear pump is tangent to the shaft, creating non-manifold geometry, so I edited the part by a few microns first).

stephen_des_jardins

I am currently making up a custom material and editing the density so that mass of the simplify part is equal to the mass of the source real assembly. I have not tested if the CofG (and inertia) numbers take if there are entered as override. I am guessing that onshape-to-robot calculates them fresh as it does masses. A minor error effect in my case but others may have more critical needs. As you can imagine, an automatic pipeline would be much better than requiring edits of urdf files. Onshape is continuing to look very capable as I explore more corners. 

NeilCooke

stephen_des_jardins said:

I am currently making up a custom material and editing the density so that mass of the simplify part is equal to the mass of the source real assembly. I have not tested if the CofG (and inertia) numbers take if there are entered as override. I am guessing that onshape-to-robot calculates them fresh as it does masses. A minor error effect in my case but others may have more critical needs. As you can imagine, an automatic pipeline would be much better than requiring edits of urdf files. Onshape is continuing to look very capable as I explore more corners. 

You can manually override the mass and CofG without having to guess a density, but don't know where onshape-to-robot gets its info from.

qiayuan_liao

This is awesome! It is possible to accumulate the mass and inertia of each part and set (overwrite) it to the simplified one automatically?

NeilCooke

qiayuan_liao said:

This is awesome! It is possible to accumulate the mass and inertia of each part and set (overwrite) it to the simplified one automatically?

Unfortunately not, because bodies copied in-context have no mass information available to read.

S1mon

@NeilCooke

I was about to ask why this wasn't a Published FeatureScript, but then when I opened the link above, it is. So why does this search fail:

I have to say that the fastest way I know to search for a FeatureScript for me is still to search the Forums and look for the post where someone has introduced it. This relies on my memory and knowledge that "hey I remember that Neil wrote a Simplify feature... where is it??"

Why is this so hard to make work?

NeilCooke

@S1mon I don't know. Seems to be only that one so I've created a ticket for it.