Origin of new parts in an assembly

Hi. I'm fairly new to SolidWorks and have a question.
What controls the orientation of the origin when starting a new part in an
assembly? For example, say I have a part that's a cube in an assembly file.
I want to start a new part on the top of the cube. I click on the top
surface to position the initial sketch plane for the new part and the origin
is placed at the back left corner with the x axis pointing to the left--180
degrees from what I'd expect.
Does the user have any control over the rotation of the origin, before or
after placement of a new part?
Thanks...
Brian
Reply to
Brian Mears
Loading thread data ...
"Brian Mears" wrote in news:guudnb1ON5T18GXdRVn- snipped-for-privacy@comcast.com:
You can use the sketch modify tool to alterthe orientation of the coordinate system, and there is a tool to align a sketch to a model edge.
The rules that govern the default orientation of the sketch axis are readily explainable with some graphics. I have seen such a diagram, but I can't remmeber where. Somebody here will know, though.
Reply to
Dale Dunn
I know of the sketch modify tool, but it seems that it only works after sketch geometry has been created--in other words, I can't rotate the sketch origin BEFORE creating any geometry.
What's the tool to alight a sketch to a model edge?
Also, if there's a diagram as you mention below, I'd love to see that... if anybody has it, can you post it? Thanks for the help!
Brian
Reply to
Brian Mears
I wonder if perhaps you're getting hung up on something that's not really important. One thing to realize -- when you insert a new Part in an Assembly you create an InPlace mate. That mate isn't NECESSARILY what you want to keep . . . unless you REALLY want to link features to other Parts in the Assembly, and even then the InPlace mate isn't necessary. Personally I recommend creating as much of your Part as you like, then exiting the Part, deleting the InPlace mate and creating geometric relationships to locate your part in the Assembly. Doing it like they teach you in class -- creating a tapped hole to line up with a clearance hole -- can be valuable, but such in-context relationships are a double-edged sword and you have to watch them, ESPECIALLY if the Part you create is going to be used in more than one place. As mentioned, you don't need an InPlace mate to keep such a relationship anyway, and you don't need to have your X, Y and Z axes coincide between parts in an Assembly. That doesn't really buy you anything valuable. Worrying about it is counterproductive. Just insert your new Part on whatever Plane or face is useful, create your sketches and features and carry on. It's MUCH more important to learn about what is going on in SolidWorks as you make your sketches fully defined (and you certainly should make them fully defined -- and idependent except where you really need to maintain in-context relationships) than it is to keep axes the same from part to part. Having come out of training class with a pretty good idea of how to get what you want from SolidWorks by hook or by crook you may think that you have a good handle on how to make sure sketches are properly defined . . . but I can almost assure you that you don't. Spend time on THAT, not on your current concern.
Mark 'Sporky' Stapleton Watermark Design, LLC
formatting link
Reply to
Sporkman
Mark,
I agree with everything you've said. I come from an MDT background where the UCS (origin) means something. It's really just about understanding why it works the way it does. If, for example I learned that picking near the lower left corner of a face caused the origin to be placed in that corner and aligned 'normal', I might be inclined to pick there when creating new parts. That's all.
I also don't like the in-context relationships that you mentioned; I like the ability to build off of other parts in an assembly, but I do NOT want them linked in any way. That's another question... can that be turned of or disabled as you work in an assembly? In Inventor, if you hold down the CTRL key as you pick geometry, it'll inference lines, arcs, points, etc. but they are not linked in any way. I don't know if I explained that well; I'll be asking more about this in the near future.
Thanks for the response. Although I agree with you, I'd still like to know why how the origin finds its home and orients itself. Hopefully somebody has the answer. Thanks!
Brian
Reply to
Brian
Look in tools, sketch tools, align, grid. IIRC, it only works with model edges. I almost never use it.
Spork is right, this really isn't a battle you need to fight. Sketch orientation really only affects the direction of the horizontal and vertical relations, and the sketch origin is an unreliable thing. If you really need the sketch to be related to a specific direction, so it with sketch relations.
Just out of curiosity, are you one of we few former ACAD users who are actually comfortable with how to use the UCS?
Reply to
Dale Dunn
Yessir, I am. I preach its importance to my coworkers. So, it's odd that it has little meaning in SW--something I'll have to get used to. Thanks for your help--there will be more questions coming...
Brian
Reply to
Brian
"Brian" wrote in news:V snipped-for-privacy@comcast.com:
Wow. Did you also understand paperspace viewports? Our customers used to get so confused by our old 3D drawings (before MDT).
Reply to
Dale Dunn
I did. We didn't use 3D AutoCAD for very long though... only for a couple of months until we got MDT (1998 I think).
Reply to
Brian
Basically, Brian, I think you'll find that if you insert a new Part on an Assembly plane, that plane (whatever it is) becomes the Front plane of the new Part, but with the origin located coincident to the Assembly origin (different plane definitions, perhaps). If you insert the new part on a plane of a Part in the Assembly basically the same kind of thing occurs, except the origin becomes coincident with that Part origin. If you insert the new Part on a face of a component, the Front plane of the new Part becomes that face, and the origin becomes coincident with the referenced Part origin.
I'm not certain I answered your question, but I hope it helps.
'Sporky'
Reply to
Sporkman
SW2005 can turn that off so you can inference, but not reference.
WT
Reply to
Wayne Tiffany
Is that an "as you sketch" option that you can selectively use, or a system setting that is always on or off? Either way, I like that it's available...
Brian
Reply to
Brian Mears

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.