Part Studio, Assembly, In Context workflow confusion

gauthier_östervall

I am making a copy of a battery holder. 

My idea to achieve this:

1. Model the blanks (plus, middle, minus), or rather a negative of the hole they require in the part
2. Model the battery box
3. Put them all in an assembly, to give relationships (plus and minus blanks need a slider mate to be aligned, and they each need to align to the middle blank too, also with slider)
4. Once in defined relations, boolean the parts in a Part Studio to get the final part

Here is the project.

I want to use an Assembly because placing the parts in the Part Studio is a pain. I could use a number of Transforms to align the negative blanks, then Line Transform them by the pole distance in the middle blank. It seems to me that this is one of the main purposes of Assembly: give part relations that matter, and it will solve it for you.

My question:

Once I have an assembly that makes sense, should I edit one of the parts in context? Or should I create a new part studio for the merged part? Both have drawbacks. Bit the bullet and place without Assembly? Anything else?

Edit a part in context

Going back to the original PS.

• there isn't one part that is a "master" part, they're just coming together
• editing the part, I need to get the other parts from the context. It's easy to Boolean Union the parts from the shaded context, but the original parts are still in the part studio, which is confusing. In my example here, the life of a blank is: 1. created in PS, 2. Placed in ABLY, 3. Copied from context in PS. Suddenly, my PS has two of them.

Create a new Part Studio

• I can't Boolean without an already existing part. I can Transform Copy in place a context part as a work around, so that's ok.
• if I update the ABLY (here fixing the fact that plus and minus blanks are touching), I cannot update the context in the new PS. Missing Primary Instance. I'm trying to manually give one as per the documentation, but I can't seem to:
  
  There is no mention of context here.

The questions are:

1. How would you solve this construction?
2. Why can't I give a primary instance, if it is missing?

GWS50

I would model these parts in a Part Studio and use the sketches to define the relationship between the parts so they are modelled in the orientation that you need them, then do the boolean in the Part Studio. If using the Subtract you can choose to keep the tools and offset surfaces to create any tolerance gaps all in one dialogue box.

https://cad.onshape.com/documents/f0f12f515fae11215ac4353b/w/c27a42766984bdc4ecd9445b/e/9db6bdfed6fcb767de4c06e6

Apologies if I have misunderstood but I hope this helps

gauthier_östervall

@GWS50 No, you're right on. Thanks for the tip. I've had the recommendation to skip assembly for the creation of new parts before. In this case it totally makes sense. I have other use cases where I want to "free hand" place components then merge, sometimes with some contraints (where the assembly shines), and that's where the Primary Instance issue really is in the way.

GWS50

Being able to build several parts in one part studio with relation to each other is a powerful design feature in Onshape. While in-context editing is useful it can be quite easy to lose track if there are more than one or two in-contexts. I'm hoping that Onshape will come up with a way to show the links and effects other than just naming the instances. A graphical method might help but it is a tricky problem.