CAD Forum

I recently start looking into SSP but cant seem to wrap my head around it...

I do see the value of SSP when it come it a large assembly, but i am abit lost when it come to small to medium size assembly (<20 component? excluding fastener)

1. Is there any added value in using SSP for small to medium size assembly compared to master modelling
For example, if i am modelling a drawer, is there any reason to model it using SSP instead of master modelling? 2. How is the (critical) purchased part (eg: PSU) being handle in SSP?
In master modelling, i often just insert the critical purchase part, mate them using move body and build my master model around them. How is this being done in SSP?

3. How is the sketch and reference geometry (plane, axis, point, etc) being handle in SSP to prevent clutter
A lot of time my ssp ended up with a large number of sketch, plane, making the part look real complicated (when in fact it is not lol) and took a huge amount of time to find some info or a specific plane
My personal preference of using infinite line to indicate a symmetry sketch make the SSP sketch worse too
What should be the proper way in handling all these reference geometry in SSP?

I know very little about SSP, but here are some resources on it.

Here's my quick summary on SSP. It is a way to convey information across parts and assemblies.

No one says every part in your assembly has to be driven by the sketch. Don't create artificial rules that stop you from working efficiently. If there are places where using a sketch or other geometry makes it easier to design your assembly, then go for it, but don't feel like if you are using SSP it has to control everything. Use it where it makes sense.

1. Yes if you will be making multiple variations of it, particularly in production volume. No, if this is a single thing produced once with the capability to change based on customer or design feedback. In short, it depends. Expectations can sting: what did I expect to change, and what did I expect not to change? I am usually surprised by which is which. Effective SSP, in my opinion, relies on your assessment of what variables need to be adaptable, and which are driven along with the adaptive ones. You can always implement new references within the SSP to adapt to what you had not expected.

2. This one is easy for me, and may not apply to your use. Almost everything in my SSP assemblies is a purchased part, except for pipe, steel weldments, and maybe some custom parts like a containment shielding panel. I mostly use Planes in the SSP for driving primary mates, and secondary mates can be tied to the primary part. This means that "stem" items are entirely on the SSP refs, "branch" items are partially on the SSP refs, and "leaf" items are only related to the "branch" it is on. That's a darn good metaphor that I should remember. I make sure that components have appropriate internal reference entities to accept useful mates upon planes and axes in the SSP.

3.a. I love Clutter! I name things appropriately so I can find it. I select mate references from the tree, by name, and not in the visual workspace. If it begins to expand past the vertical capacity of my feature tree, I can cluster meaningful portions of the references into categorical folders. Folders in the SSP should match default assembly folders, for greatest ease. Unless I'm dissecting and altering the SSP, it stays hidden.

3.b. You need more clutter. Begin with redundancies. For example, I have a plane to determine position (Coincident, Distance) and a second identical plane to determine orientation (Parallel) which usually applies accessibility or clearances to operator handles. Then, I can relocate or flip one without affecting the other and everything else tied to the other. In your drawer example, you seem to begin with the assumption that you will have one knob and it will be centered on the symmetrical plane. What about multiple knobs, or asymmetry, or such? Duplicate the Right Plane with an identical Symmetry Plane and maybe even a third Lateral Knob Plane. If you have Sketch symmetry, that centerline can be tied to the Symmetry Plane within multiple sketches for different purposes.

You may disagree.

Is there any use for master modeling in PDM?
I can not see it.


Also:
Why is never envelope/envelope publisher mentioned in those discussions?
Am I missing something?

berg_lauritz wrote: ↑Thu Dec 09, 2021 2:03 pm Is there any use for master modeling in PDM?
I can not see it.

I'm not sure PDM changes the need for master modeling. It's just where you store and control your files.

jcapriotti wrote: ↑Thu Dec 09, 2021 3:37 pm I'm not sure PDM changes the need for master modeling. It's just where you store and control your files.

I should have specified properly:
For the concept I like the master model.

Using save bodies or anything similar is just so painful with SolidWorks PDM that I can not see a proper use for this. This problem comes from PDM though...

berg_lauritz wrote: ↑Thu Dec 09, 2021 2:03 pm Is there any use for master modeling in PDM?
I can not see it.

Like Jason said above, Master modeling has nothing to do with PDM. I have used both techniques and saved them in PDM. Its all about what best fits your workflow.

as for save bodies, check this out: https://blogs.solidworks.com/tech/2017/ ... nique.html
I hope that helps

ResidentAtLarge wrote: ↑Fri Dec 10, 2021 9:57 am Like Jason said above, Master modeling has nothing to do with PDM. I have used both techniques and saved them in PDM. Its all about what best fits your workflow.

as for save bodies, check this out: https://blogs.solidworks.com/tech/2017/ ... nique.html
I hope that helps

I will re-visit this to get a better grasp.
Thank you.

I may annoy some people saying this, but it's true. SSP is really just layout sketch technique. It doesn't need a special made up name. There's a reason people ask what SSP is - because it's not really a thing. It's a name looking for relevance. It's just layout sketch. Layout sketch has been around for a long long time as part of the software. It was in the standard SW training material from way back.

And then SW confused things by creating an assembly feature actually called Layout. That feature is different from the assembly based sketch. It's just a really bad idea to give things like LAYOUT and PDM proper names when generic names also exist for something very similar.

Skeleton techniques, as far as I know, started in Pro/E. I don't know anything about that, but I think there is more to it than just a name in Pro.

Layout is really just an intermediate step between top down and bottom up.

Bottom up has no references. Well, the assembly references the part, that's the extent of the references.

Top down (in-context) is where parts reference one another in an assembly. So the reference between part 1 and part 2 contains the assembly file. So each reference in part 2 contains links to part 1 and assembly 1. There is always the danger of creating circular references, or daisy chained references that require multiple passes to get everything rebuilt properly.

Layout is somewhere in between, because the sketch (layout sketch) is at the assembly level, and part 1 and part 2 can reference the sketch in the assembly. Some people make the sketch at the part level, and that removes the circular reference, but can create other problems. I prefer the layout technique over in-context.

The problem with this is that it's kind of a circular reference. The assembly references the part, and then the part references the assembly. This starts to slow things down, and the file references start getting confused.

Whenever you use references like this, you have to make sure that you use a structured logic. Make sure that references always go in one direction. If you have references between the part and the assembly sketch, references between parts can complicate things. If you also have backwards references between part and sketch (part edges or sketches driving sketch elements instead of or in addition to sketch elements driving part edges or sketches), you're looking for trouble. Solidworks is supposed to be able to detect circular references, but it doesn't always get them, and it doesn't ever identify convoluted references that cause looping rebuilds.

Master model is different. It usually skips the assembly reference. You make part 1, and then split it into part 2 and part 3, and then put 2 and 3 back together in an assembly. Master model is best used for 2 reasons: 1) to make a smooth shape in one part that would be difficult to make across multiple parts, also allowing you to centralize change where this is a single shape that affects multiple parts in an assembly 2) to try to compartmentalize rebuild time when you have a very complex exterior and an equally complex interior for a single or multiple parts.

Master model doesn't use an assembly until the end of the process when you have the individual parts made and bring them back together as an assembly. You can use the origin for this, since all the parts share the same origin.

The moral to the story is that it's easy to get yourself into trouble with layout and also with in-context. It is less easy (but still possible) to get yourself into trouble if you use master model (especially if you start combining master model with in-context).

And then you've got the additional complications of combining in-context with 1) configurations 2) underconstrained parts 3) master model. If you do any of these you're asking for trouble. Can they be done? Yes, but mostly by either accident or a really expert knowledge of what you're doing. Anything in between will get you in trouble.

On top of this, you have history. The assembly is non-history based, but parts are history-based. Relations between parts in the assembly ignore history, but master model uses history. This all gets very confusing, and it's the reason people get themselves in a lot of trouble when trying to work in-context. People are afraid of in-context because they don't understand it.https://dezignstuff.com/why-are-you-so- ... xt-design/

Master model can definitely be controlled with PDM. The master model may not be used in the actual production assembly or drawing, but it is a reference that is recorded in the software. It will probably show up as an in-context relation without an assembly.

matt wrote: ↑Fri Dec 10, 2021 1:17 pm I may annoy some people saying this, but it's true. SSP is really just layout sketch technique. It doesn't need a special made up name. There's a reason people ask what SSP is - because it's not really a thing. It's a name looking for relevance. It's just layout sketch. Layout sketch has been around for a long long time as part of the software. It was in the standard SW training material from way back.

I'm not annoyed, but a little confused. Please show me some documentation on your claim. I've looked and there is scant information on this technique by any name you call it. This is what I was able to find and it's not what I'd describe as "SSP":
https://knowledge.autodesk.com/support/ ... 9-htm.html

The method AFAIK is used in the automotive and aerospace industries, but I have no idea what term they use to describe it.