How to model a big project?

brendan_romano_romano

First of all, shout out to the OnShape team! Thank you guys for creating such a revolutionary modeling tool, wish you all the best in the new year!

To begin this discussion, I would like to set a few background information:
1. I am new to 3-D modeling with Standard subscription. I have taken all the instructor-led courses as well as self-paced courses.Overall, I have general understanding of the skills but not yet fully comprehended them.  
2. For the sake of this conversation, consider this "big project" as "building a house". This house is already built, which means detailed Structure, Electrical and Plumbing drawing are all available.

My goal is to re-create this house in OnShape based on available drawings. I wish to practice the knowledge learned through the courses via this re-creation process. I think this would be a good way to become better at modeling and build my "designing sense".

All I know at this stage is I want to model this house in 3 portions(structural, electrical, plumbing) as this allows me to hide irrelevant portions when I talk to specific contractor. 
(Please note: I use "3 portions" on purpose because I have not yet fully understand when to use "part studio", "assembly" or perhaps "multi-part part studio")

I know I sounded clueless, but that's how I felt at the moment.

Naturally my questions are:
1. What do I need to think about in order to plan it right?
2. Where should I start?
3. Along this process, where/who can I bounce ideas from? (I think the word I am looking for is "mentorship")

Thanks!

MBartlett21

I'd suggest modelling up a simplified model of the house in a part studio then creating new part studios and deriving the simplified model for each of the the three portions of the design.

You can then insert each design into a separate assembly then insert those into a big assembly,using display states to hide and show them.

MBartlett21

I'd suggest modelling up a simplified model of the house in a part studio then creating new part studios and deriving the simplified model for each of the the three portions of the design.

You can then insert each design into a separate assembly then insert those into a big assembly,using display states to hide and show them.

billy2

Simply, I'd start like mbarlett21 suggested and break the house into workable bits.

Simplicity means you'll probably be dealing with part studios, but this will limit your ability to break up bits. I think this is where you should start being a beginner.

Please understand your geometry, walls & framing will render easily, where plumbing will require more. Cylinders are harder to show than rectangles. If you really want to be in control, you can have varying resolutions at different levels of your bits. Larger part studios (component count) can be set at a lower resolution as they will be viewed from a global distance while a lesser part studio can have a higher resolution used when zooming for a closer look. For instance, while viewing the entire house, would you mind if the plumbing looked hexagonal? Possibly not, when zoomed out you can't see the plumbing definition so leave it's resolution course.


There hasn't been a lot of work to optimize large assemblies inside OS yet. Don't get me wrong, OS is much faster than SW for me and what I'm doing. One camp thinks you need a super computer with 48 gig of ram while the other camp thinks a little management will get the job done more effectively. I'm in the management camp. With OS you're only managing display lists, geometry is on the server and currently pose a lesser issue than previous CAD systems. Your geometry is simplistic, rectangles are simple to render.


In the past, when at your stage in a project, I consider the following:

1. where's the top
2. what are the deliverables
3. can it scale up without performance degradation
4. who's working on it, how many people, what departments
5. how do I manage the who, what, where & when
6. how do I manage BOM's and procurement
7. schedules and performance
8. control engineers working to a project standard


I don't think there's been a lot of this going on here yet, but it's right around the corner. Me, I want to be able to make things disappear in my design and then make it come back easily. When I'm working, I only want to see what I'm working on. My top would be an assembly with a detailed sub-assy structure that gets published for engineers to follow. I test peoples understanding before allowing them to work on a large assy. I feel I'm building a snow flake and it's too easy to destroy. A large assembly to me is a building full of automated equipment and each line is represented. How many 6mm x 25lg SHCS did I use? Actually, that's common stock and don't track that stuff. The largest assembly I've put together is 3 buildings full of equipment with the origin of the top being defined as the sites flag pole located at the entrance to the main building.

Your house, where's the top? Is it your yard or just the foundation? How do you know how to hook your house to city facilities?



Anyway, you asked a great question.


 

edward_petrillo

I made a fairly complete model of a modest-sized (2000 sq ft) 1 1/2 story house as a guide for bathroom and interior renovations including new DWV (PVC) and supply (PEX) plumbing.  The model was based on on-site measurements rather than drawings. It proved to be extremely helpful for routing wiring and piping.  If you intend to use your model for a similar purpose, here are some lessons learned.  The overarching principle is to include only the detail that is needed for the work you plan to do.  
1) Model the foundation, each floor/ceiling platform, and perimeter walls for each story as separate parts studios. Make a master layout sketch and derive it into each PS to maintain a common origin.  Build up wall structures with top and bottom plates and studs (use linear part patterns to replicate studs.)  Join the dozens of individual frame members into a single part with boolean union.  Add the other wall layers (sheathing, rigid insulation, siding, drywall) and boolean them as well.  Booleans keep the parts count way down; you can always roll back in the feature tree to make changes.
2) Model interior wall groupings as separate parts studios using a similar approach.  Make a door/window sketch on the horizontal plane and extrude openings.  
3) If you've maintained a common origin in all of your studios, the top-level assembly should snap together without any mates.  Group it all together.
4) Avoid fully modelling plumbing and electrical systems unless absolutely necessary.  You can model a PVC DWV system by mating imported parts in an assembly.  What's really important is the penetrations in walls and floors and the stud or joist bays where the pipes and wires run.  
By dividing the house into logical subunits, you can work on only the areas that require attention without degrading performance.