when you mate in an assembly you can selest use for posioning only, after that you can rmb on the part and select fix.
the part has no mates and is fixed in the assy
Learn to use master layout sketches to construct parts and assemblies.
Don't let the 99%ers tell you that constrained sketches are necessary. Once a sketch is closed, nothing moves, everything stays where you left it.
Sketching everything "Fixed" would be worse than creating a fully defined sketch.
If an edit to a fixed sketch was needed, the sketch elements would have to be unfixed, edited and then re-fixed.
Fully defined sketches are not necessary, but for the type of parts I create, I prefer to use them so that I can predict the affect of an edit.
Roland is correct in stating, "Once a sketch is closed, nothing moves, everything stays where you left it.", however, if an element in a sketch is moved, other non-constrained elements may move unpredictably, or not move as needed. Design intent plays a big role. If a line is to remain tangential to a curve, or parallel to another line, that constraint needs to be set. Not necessarily fully defined with dimensions, but constrained to maintain the design intent.
I agree with you about using fully defined sketches. I was talking to a guy from our VAR the other day and he told me about a draftsman who didn't take the time to define his. Some sketch element got inadvertently moved just a little bit, he didn't realize it, and the part went into production. It cost his company several hundred thousand dollars and cost him his job.
Think about working on someone elses part where the the sketches are not constrained.
You need to edit a sketch and lines get moved.
Then you have no idea what it is suposed to be?
I do think about it. That's why I always start by making a copy of models being changed to cross check. This is actually more important when sketches are fully-yet-haphazardly constrained by whatever hack may have originated the model.
I'm not really understanding why you'd need to re-apply any relations if things are modelled correctly. Being a fan of getting things done quickly myself, I can safely say that doing things properly is the best, and most efficient way to do things when looking at the over-all development time and life cycle of a product.
Gerard Boterman wrote:
. . . This results often in having to restore, redefine or even redraw parts -- very time consuming and a huge contrain in my productivity.
To overcome this problem, during the design process, it would be great if I could switch off any relations, definitions, etc, and draw everything 'fixed'. . . .
No trouble doing what you want with the program, but the combination of statements above really makes me wonder. The whole point of relations - sketch relations and mates - is editing. If you can design it and never change it, then forget the relations. But if you revise, or copy and make modifications, the relations save a ton of time. You do have to create relations that match your design intent.
If you do it right, it is a thing of beauty. For me there is nothing more rewarding in SolidWorks than to go back into the very root of a complex part, wreak havoc with dimensions and form, and then see it all update without error and appear in the assembly just where it ought to be. A mess of time can be saved that way.
Have you taken any SW classes at the VAR?
You need to understand how SW works over the direct modeler approach, direct is nice for quick design and changes...but once you learn the constrained modeler and make your design intent work for you it is faster down the road to make changes.
for some parts if you use equations all you have to do is change one dim and the whole part updates instead of having to select all the faces you need to move.....
you just have to use a little more foward/look ahead thinking.... direct is like playdo or silly putty and contstrained is like cutting a something in real life, if you cut it wrong you you can't just stick more putty back on...plaining is the key. SW is like how you would machine it...this first that secound.....direct who really cares...to a point...putty.
but SW really needs to have both now!!! like SolidEdge ST or Catia V6
Gerard, work on your parts within the context of the assembly or sub-assemblies. Fixed part feature sketches are not the way to success with SW. Roland's suggestion of layout sketches is excellent whether the sketches are part of the assembly or in the base part of the assembly.
Thanks guys, for all the good advise.
I can clearly see what the designers of Solidworks tried to achieve with defining all the constrains and design intends (e.g. a line to be always tangent to an arc)
I have 25+ years of design experience and believe all CAD platforms have pro's and cons.
The very reason for my question, while learning the interface of SolidWorks, is that I need to go over so many more steps to do exactly the same as what I used to do before, taking so much longer to achief the same type of design work. Drawings getting so much more complex with long feature design trees, creating huge files. It might be is ok for experienced SW designers, but what if you work with many designers who are less experienced and you have to work with complex parts that were not created in the SW perfect way? My problem with SW is probably working with 'dirty' designed parts (incorrect design intends) and 'foreign models' that have missing design trees.
A lot of younger designers who design parts but not having the experience what actualy can be produced by machining and toolmaking.
My previous program did not restrict me with any of these, while still having the options to edit features by just selecting and changing or removing if required. No long, complex feature trees, no foreign models. Everything on screen are native, editable, and 2D and 3D exists in one environment.
This is why I try exploring SW using in a similar way, then also combining the strenghts of SW like mating parts and movements.
I guess I am just a bit frustrated with my own performance in getting designs done clean, accurate and fast as I used to.
Time will tell if I will ever prefer SW over my previous program, using it for the type of work I do.