CAD Forum

Folks,

I know there will be differing opinions, which I will keep mine to myself for the time being ,

When your engineers are designing parts, do they build in relation to 0,0,0 of the world, OR...do they build based on location in an assembly, so that 0,0,0 of every part in the assembly are at the same position, effectively building parts in outer space...

I can clarify if needed, for me, this has been an on going discussion since 3D Design software started..

Thanks,
Brian

Most of my new parts get the first extrude on the plane I choose for the sketch, with the other 2 planes crossing at the center of the extrude.

Yup...lol...COW's are my job...

Master Sketch, so all share same origin.
I build fixtures. So I'll put customer part in assembly at origin and build fixture around it.
Once the parts are modeled, just insert them in assembly fix to origin.
No assemble required.
Battery not included.

It really doesn't matter. Whatever easier and faster.

BrianHoerner wrote: ↑Fri Mar 26, 2021 1:13 pm Folks,

I know there will be differing opinions, which I will keep mine to myself for the time being ,

When your engineers are designing parts, do they build in relation to 0,0,0 of the world, OR...do they build based on location in an assembly, so that 0,0,0 of every part in the assembly are at the same position, effectively building parts in outer space...

I can clarify if needed, for me, this has been an on going discussion since 3D Design software started..

Thanks,
Brian

I think it depends entirely on the situation, process etc. When doing machines I tend to make the 0,0,0 of the sub/a's 0,0,0 of the top level assy...assuming those parts aren't moving in relationship to 0,0,0. If they are moving in relationship to 0,0,0 then I will make the S/A's 0,0,0 whatever to the 0,0,0 of whatever S/A it's connecting to that it doesn't move in relationship to.

This is obviously dependent on how complex the system is.

I tend to mate parts to whatever they are mated to in S/A...and that's not a hard and fast rule either.

So in short I try to do it in a way that meets the needs of the design, which is rarely the same.

Edit to add: Typically people that insist that something be done exactly a certain way all the time either are working with something that does not change or just don't have enough experience to know that the same approach to everything is not always the best approach.

I build according to the needs of the project and the methods and policies of the project team.

BrianHoerner wrote: ↑Fri Mar 26, 2021 1:13 pm Folks,

I know there will be differing opinions, which I will keep mine to myself for the time being ,

When your engineers are designing parts, do they build in relation to 0,0,0 of the world, OR...do they build based on location in an assembly, so that 0,0,0 of every part in the assembly are at the same position, effectively building parts in outer space...

I can clarify if needed, for me, this has been an on going discussion since 3D Design software started..

Thanks,
Brian

Usually with the stuff I work on, it's just one complex part or maybe a small assembly. I do both - each part with its own origin, and the assembly where all parts have the same origin. In general, the requirements of the project suggest the approach.

Preferences:

1st preference is to model single parts.
2nd is master model with a single part broken into multiple parts, and possibly brought back together as an assembly.
3rd preference is single parts with bodies for reference.
4th is individual parts brought together into an assembly. But I don't use bodies where an assembly should be used.

What actually happens:

1) usually I model the parts bottom up, centered or otherwise located from the part origin, and then mated into place using part geometry or possibly a layout sketch

2) for more complex things (one large shape comprising several individual parts), I model a master model, and split it into bodies, inserting each body into a part. The detailing is finished in the individual parts. If the parts have to come back together into an assembly all the parts already share a common origin.

3) If I have to start the parts independently, and they still require relations between them, I will insert the part and get the relations that way rather than working in-context in an assembly.

4) very rarely, and usually just for demos, I connect parts parametrically (size and position) to a layout sketch. I don't think I've ever actually done this for a production assembly.

Traditionally, I've been using the origin and modelling symetrically around it for the most part. I'm starting to seriously rethink that process though. It's too early for me to give good details....but SSP looks more attractive.

Each of my Parts has its own origin, though I do try to keep the top plane consistent between components that will intersect or rest on the ground, just to make mating easier. Many of my Assemblies are 100+ feet long, and I have a large library of common Parts and Assemblies that are used in multiple projects, so having a common origin would be a nightmare, or in many cases impossible.

I vary as is most convenient.

My goto is always around the origin. This is because most of my parts have symmetry.
The default planes are renamed XY, XZ, YZ

We are free to change the origin as suits, but if we do we must rename the default plane.

For example here the main component is fixed (shares the same axes as the assembly) but the pegs have one of their Default planes renamed FACE.
If a component sits on the floor the Top Plane is renamed FFL (Finished Floor Level) We have similar conventions for other scenarios.
For example renaming the Front Plane -> FACE1 or FACE2 (Front & Back)
or the Right Plane -> EDGE1 EDGE2 (Left & Right)
etc..
whilst retaining the XY, XZ, YZ naming convention for mid planes.

We can't really use Front, Right & Top because our components often fit together face to face so it becomes exceedingly confusing. Port & Starboard would be a better fit.

Rob wrote: ↑Sat Mar 27, 2021 10:08 am I vary as is most convenient.

My goto is always around the origin. This is because most of my parts have symmetry.
The default planes are renamed XY, XZ, YZ

Most of mine do also. The Right Plane especially is almost always down the center, and the same is often true for the Front Plane (though less often). Parts that don't contact the ground are usually centered on the Top Plane.

If I have a primary symmetry plane, I rename it with "SYMMETRY" in the name (yes, all caps). It helps me. It helps others. I've had people thank me for it.

My 2 cents...

If they are bottoms up parts, then the Base feature is centered on Part's XYZ, and almost always base part sketch is centered on the mirror plane (i.e. right plane) and extruded>midplane.

If you have a master with multi-body parts, then this is a non-issues as all the derived parts will be on the master's XYZ - a good thing!

With master modeling, is it still an issue with drawings and updates moving views of parts off the sheet? Would be nice to get a coordinate system feature that had planes, origins and axes built in like NX has.

Boring here.... parts all at the origin, assemblies too.

@jcapriotti - Jason, are you talking about multi-bodies in a drawing or derived parts thru Save Bodies? Can you expand on the issue with drawings and updates moving views of the parts off the sheet? - I've never had that issue?

mbiasotti wrote: ↑Tue Mar 30, 2021 10:00 pm @jcapriotti - Jason, are you talking about multi-bodies in a drawing or derived parts thru Save Bodies? Can you expand on the issue with drawings and updates moving views of the parts off the sheet? - I've never had that issue?

It's been a while since I tried it but a part built on a long master part sketch where the length can change by a large amount. Seemed the view would move off the drawing sheet if the position changed. This was for parametric designs. I remember some old conversation either with a dev or reseller about how the view center needed to stay put regardless of where the part was in 3d space.

@mbiasotti Here's an example, this pertains to Master modeling for parametric designs.

Before After

@jcapriotti

I would recommend that you lock your drawing views, plus if you do any section or detail views lock in your Detail or Section Line to the part by dimensioning it off the part edges etc, that way when you do make drastic size or placement changes your part behaves like you need it to.

Roasted By John wrote: ↑Wed Mar 31, 2021 7:18 am @jcapriotti

I would recommend that you lock your drawing views, plus if you do any section or detail views lock in your Detail or Section Line to the part by dimensioning it off the part edges etc, that way when you do make drastic size or placement changes your part behaves like you need it to.

Locking view position has no effect, the view isn't moving, the part is, relative to the origin. Need an option define view position based on the part CG or something, maybe a coordinate system added to the part.

Coulda said that works, because here we do a pack and go and if the views are fixed after we change the design I don't remember that the parts moved off of the drawing sheet, if the view is fixed.

@Roasted By John

If your parts are built around the origin, then that is generally true. In this example, the part is built on a Master skeleton sketch where the part is located far from the origin. As long as the part's location doesn't change much (static design), then no problem, but we do parametric designs so its position relative to the global shared origin changes.

BrianHoerner wrote: ↑Fri Mar 26, 2021 1:13 pm Folks,

I know there will be differing opinions, which I will keep mine to myself for the time being ,

When your engineers are designing parts, do they build in relation to 0,0,0 of the world, OR...do they build based on location in an assembly, so that 0,0,0 of every part in the assembly are at the same position, effectively building parts in outer space...

I can clarify if needed, for me, this has been an on going discussion since 3D Design software started..

Thanks,
Brian

Depends on how my project is going to be set up.

If I am making something small and quick, then everything is started at 0,0,0 and then moved and mated at the assembly level (except the base plate....or whatever is being fixed)

However, if I am using the Master model/SSP method, then everything is in Assembly location. Either way is no longer a big deal anymore, except for programmers and machinists who don't know how to use their software. In which case, we will probably not be using them for long....