Constraints/Dimensions or No Constraints/Dimensions in 3D Modeling

[GreenTwin]

Bazzer-

I am sure it is as puzzling for others as it is for me that I don't dimensions sketches.
And I have never even been aware that I was suppose to be fully defining sketches.

I honestly don't even know how to fully define a sketch.
I don't know what it means to fully define a sketch; or what the implications of it are, other than the bits and pieces I have read in this thread about how this "could" cause trouble. It has never caused any problems for me that I am aware of.

Jason makes a good point that some things in a SW sketch may fully defined automatically, it even if one is not aware of how that is occurring.
And as Jason also says, the dimensions of a sketch are in the database, but I don't go an extra step and repeat those with graphical dimensions that are visible on the screen, since if the dimensions are defined in the database already, why repeat that data with extra steps? Seems like a lot of duplicate work.

I would go back and study it all again, but don't have time to do that at the moment.

Perhaps it would be good practice to force a sketch to be fully defined and dimensioned, but my arguement would be that if there was really a serious problem with the sketch not being fully defined and dimensioned, then the program would not be able to use it to create the 3D part, or the 3D part would be unstable, neither of which is true for me.
10 years of 3D modeling without problems sort of speaks for itself.

As Jason mentioned, if you are doing a lot of manipulation of the sketches in the sketch editing part of the 3D program, it may pay to nail things down a bit more.
I do manipulate my sketches in SW sometimes, and I still don't have a lot of problems, but occasionally SW does do unexpected things due to relations that the program has automatically added to the lines.

But bottom line is importing sketches from another 2D program into Solidworks is a rather normal thing I think.
2D sketches are rather generic; there is really nothing special about them, and I would guess that just about any 2D sketch from any program could be imported into Solidworks and used successfully.
Makes me wonder if folks are just not aware that they can import 2D sketches into their sketch plane? or whether that feature is available in programs other than Solidworks?

Doing all of your sketching in the 3D program is like buying gasoline from Exxon, and saying that your car won't run on any other brand of gasoline.
Gasoline is gasoline for the most part.
We have a refinery in town, and so if you visit the refinery filling depot, where all the tanker trucks get filled, you will find almost every single brand of outlet in the whole region labeled on the trucks, ie: Shell, Exxon, Texaco, BP, Chevron, etc., etc.
They all fill up from the same tank at the same refinery, using the same gasoline.
The only difference is the small amount of additive that each manufacturer may add to each truckload at some place other than at the refinery.

Seems foolish not to use the most effective and efficient method to build 3D models, just because someone says you should only sketch in the 3D modeling program because that is what they do.

The 3D modeling program enables one to design the engine.
The 3D printer allows the patterns to be printed.
The foundry allows the engine parts to be cast.

While the 3D modeling program is important, it is enabling the things that follow, not vice-versa.
There is a lot more to making engine parts than the exact method that you use to create the 3D model.

Edit:
The method I use to import sketches from Autocad to Solidworks is quite simple.
1. Create a closed sketch in Autocad.
2. Select the entire sketch, and pick "COPY" from the pulldown menu.
3. Toggle to Solidworks, where you should be on a sketch plane, and from the EDIT menu, pick PASTE.
4. Move the sketch to the correct location.
5. Extrude your shape.

It is a very quick and effective method.
I wonder how many folks have ever tried it that are also using AutoCad or some similar 2D program?

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[Jasonb]

You do however give the elements that make up your sketches "values" such as length, radius, diameter. Which a lot of others refer to as dimensions.

May be efficient for you PAT but having to go back to Autocad to make revisions to a sketch and then reimport and then edit subsequent work in SW does not seem efficient to me or several other posters here. i speak from experience of designing in Alibre and doing CAM in F360, right pain if something wants altering after it has been exported.

I don't think any of the other posters in this recent batch of CAD threads would say importing a 2D sketch into the 3D CAD is normal, possible yes but not the usual way it's done

Also worth saying that I don't have to go and enter lengths to dimensions a second time if I want to see the dimensions while sketching Alibre just picks up what I have entered in the boxes and I think SW auto dimension does the same so it's efficient to me as no double work as you describe.

There is also the issue of having to buy two separate programmes, a 2D and a 3D and pay any yearly fees. Then the new user would be faced with learning two programmes before they could become efficient time wise

 

[GreenTwin]

May be efficient for you PAT but having to go back to Autocad to make revisions to a sketch and then reimport and then edit subsequent work in SW does not seem efficient to me or several other posters here.

You keep repeating that, but I don't do that, and never have.
That would make no sense to do that.

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[GreenTwin]

There is also the issue of having to buy two separate programmes, a 2D and a 3D and pay any yearly fees. Then the new user would be faced with learning two programmes before they could become efficient time wise

Yes, this is a valid point.

But I would guess a number of folks come from the Autocad world, but that is just my guess.

Should we do a poll? ie "Who has a 3D program and a separate 2D program on their computer?".


POLL #1:
Post here if you have a 3D program, and a separate 2D program such as AutoCad or similar program on your computer. (Yes/No).
We will do a headcount.

POLL #2:
Post here if you have ever copied a 2D sketch from a 2D program and pasted it onto a sketch plane in a 3D program. (Yes/No).

POLL #3:
Post here if you were aware that you could copy a 2D sketch from a 2D program and pasted it onto a sketch plane in a 3D program. (Yes/No).

.

 

[GreenTwin]

I kind of suspect that people don't do the copy/paste sketch thing because they are not aware you can do that (the users who have two programs).

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[ajoeiam]

Yes, this is a valid point.

But I would guess a number of folks come from the Autocad world, but that is just my guess.

Should we do a poll? ie "Who has a 3D program and a separate 2D program on their computer?".


POLL #1:
Post here if you have a 3D program, and a separate 2D program such as AutoCad or similar program on your computer. (Yes/No).
We will do a headcount.

POLL #2:
Post here if you have ever copied a 2D sketch from a 2D program and pasted it onto a sketch plane in a 3D program. (Yes/No).

POLL #3:
Post here if you were aware that you could copy a 2D sketch from a 2D program and pasted it onto a sketch plane in a 3D program. (Yes/No).

.

I have both LibreCAD and FreeCAD
(I can get at least some things done in LibreCAD - - - FreeCAD - - - - I'm still out in the weeds!!!!)

No

No(!!!!!!!!!)

 

[Jasonb]

I use 3D programmes and don't have any 2D programmes so could not create a 2D sketch in a 2D prog even if I wanted to import it.

No option 5 either. I know that you can and do sometimes copy a 2D sketch or part thereof from a 3D program and paste into the same 3D program either as part of the same component or to save sketching it again for a new component.

1 No
2 No
3Yes

 

[Oldiron]

Autocad LT and Alibre. I just recently had to go the other way. Draw a spiral line in alibre, cut and past it into AutoCad to divide it into even segments to do some engine turning on the cnc mill
1 Yes
2 Yes, the other direction
3 Yes

 

[abby]

I often use copy and paste between my ViaCad drawings , I am currently designing a new kitchen and have drawings for all the elements such as various sized base units.
I copy and paste these as required into the main drawing.
When producing patterns for castings from 2D drawings I often paste scanned sections of said drawings and , after adjusting size ,trace over which enables unshown dimensions, radii etc to be measured and more accurately modelled.
I found this useful for producing patterns for scale locomotive name plates where font is unknown.
I find 2D/3D ViaCad a very powerful and easy to learn use tool so I am suprised that I come across so few mentions on model making forums
although the price of the latest version is now $200 which is double what I paid for my older version.
Dan

 

[GreenTwin]

There is also the issue of having to buy two separate programmes, a 2D and a 3D and pay any yearly fees.

The yearly fee thing is a real bane.

I purchased AutoCad in the last year that you could buy a perpetual license without the yearly fee (2004).

I also purchased Solidworks as a one-time fee, with no annual fees (2011), and this is exactly why I chose this program over any other 3D modeling program.

The yearly fees on today's versions of modern drafting and 3D software can be thousands of dollars per year.

Luckily there seems to be some low cost or even free software out there that is quite powerful.

I have had people say "You need to upgrade these programs, they are ancient".
Thank you but no thank you.

Upgrading these two programs would be a costly mistake.
If it is not broken, don't fix it.

Edit:
The other trend which I am not keen on using is cloud programming.
I don't use the cloud, no matter how convenient it may be.
If your stuff is in the clouds, you don't really have posession of it, and so someone can turn off your cloud if they wish to do so.

Having your stuff in the clouds also forces you to be connected to the internet.
That is the first question I asked when I bought AutoCad and Solidworks, "Do I have to be connected to the internet to use this program?".
The answer is "No".

If Solidworks gets corrupted, you have to upload your license to the cloud, and then download it to a new computer.
I have to do this if I start having problems with a computer, or the software gets corrupted and can't be fixed.

.

 

[Jasonb]

Alibre can be had for a one off fee too, Up to the individual if they also want to also pay for maintanence/updates

I do wonder though if you have missed out on updates over the years? if you are using a nearly 12year old Solidworks that may be why you don't get on with it's sketching side of things which could be considerably improved since 2011. I know that each update I get from Alibre there are improvements to existing features as well as more new ones.

 

[GreenTwin]

Most of the engineer/architect world has moved on to Autodesk Revit, with a building model that everyone is linked into.
I refuse to buy Revit, and I refuse to link into any building model, although some insert my stuff into their building model.

Luckily I almost never work with Architects, and so I can do my own thing with my software.
I hire Architects if I need them, and they do it my way.

For a while there were some significant improvements in the 2D CAD world, but the biggest was stability.
Autocad 2004 seldom crashes, although sometimes the file does get corrupted.
Autocad 2D finally got mature, and so there was not a lot to be added to it, or probably more correctly Autodesk turned their focus to Revit, and stopped improving their 2D program (my guess).

Dassault owns Solidworks, and they are not known to change things for the sake of change.
Some of the changes to Solidworks seems to be with add-on packages to do all sorts of things, none of which are any use to me.

In order to justify a yearly program fee, the program has to have new features added which make my work go faster (time=money).
So far neither Autocad or Solidworks has added any features that allow me to get a return on the fee investment.

A buddy of mine changed to Revit years ago, and so all of his mechanical work is in 3D.
He has to pay a huge fee every year for every seat he has.
That is a lot of money to toss out the window every year.
He does work with Architects, and so he is tied to the millstone, so to speak, and is at their mercy as far as software, and many other things.
He basically has to bend over and take it, so to speak. I don't.

You cannot necessarily pass on fees and fee increases to the client, so you have to watch those carefully.

I got a notice yesterday about Solidworks 2023 coming out.
They say "lots of new features", but I don't know what those features are.

Solidworks "gotcha" is that if someone is using a different version of Solidworks than you, you may not be able to exchange files with them.
So that forces folks who have to exchange SW files to upgrade every year.

I don't exchange native format SW files with anyone, so I am saved from that.

Lets say that the annual fee is $1000.00 per year (I think some are much higher than that now), and you use a program for 18 years (or more), that is $18,000.00 for that one program/seat.

If spending the $18,000.00 will earn you $36,000.00, then well worth it, but otherwise not.

During the good years, you can make good money, but during the lean years like 2008/2009, there is no work, and so you have to be able to survive for a year or more with no income.
In 2009 I sold my office building and moved to my house, so I would be recession-proof.
I have watched my expenses very closely after 2009.
Its a matter of survival of the fittest.
Many of the A/E firms in town went under in 2008, but I made it, and I run an extremely lean operation these days.

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[GreenTwin]

Here is a link to the Dessault website.

https://www.solidworks.com/product/whats-new
This video demonstrates some of the changes.

Never Stop Evolving – Explore the Best of SOLIDWORKS What’s New 2018-2023​

I see some nice features, but sometimes some features are what I call "bells and whistles".
If you do a lot of bell-and-whistle work, you could perhaps justify an upgrade.
The auto-routing in control panels would probably pay for itself, but I don't use that feature.

Solidworks 2011 is a well defined, well refined 3D modeling program.
They don't call it SOLIDworks for nothing; it is pretty rock solid, and relatively intuitve to use.
Solidworks 2011 will do pretty much anything you can imagine doing in 3D.

Once you start the annual fee thing, it is forever; you can't turn off that hole in the bottom of the bucket, and the hole never gets smaller, it always gets larger over time.

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[GreenTwin]

I worked on a project recently where multiple disciplines designed in Revit, and I designed in AutoCad 2004.
You can import Autocad files into Revit, and that is what they do with my 2004 files.

They can extract DWG files from Revit and send those to me, to import back into Autocad2004, and I do that with base plans.

Not a perfect situation, but it works pretty well, and the file exchange has not been too demanding or frequent.

The other disciplines used the building model system for accuracy, but it is painfully apparent that no 3D modeling feature or program can compensate for a lack of design experience.

The project is only as good as the design, and the design comes from the engineer, not the 3D program.
I have seen folks put complete garbage into the 3D model, and the model does not care if the design is functional or not.

I ask people "Why did you put that device there; it won't work there".
They say "Well the program let me do it", ie: the dog ate my homework.
When they go to build the project, and something does not work, they don't care about your dog, they want a design that works.

.

 

[Richard Hed]

GreenTwin

I have read quite a bit of the recent threads and taken in your unorthodox approach to importing 2D sketches from AutoCad, all I can say is that it clearly works for you.

I would add that AutoCad had a 3D modeller called Mechanical Desktop, that programme was so rigid that it would not allow a sketch to be used unless it was fully defined and dimensioned.

Anyone else remember the awful Mechanical Desktop?

Yes, I had to teach it. It was absolute krap. AutoCAD was getting beat up by the the new 3D CADs at the time and that was thzeir quick solution to try to stop the bleeding. It only bled worse. they finally developed something much better, even so, programs developed as 3D from the ground up are all better and easier to use.

 

[petertha]

But bottom line is importing sketches from another 2D program into Solidworks is a rather normal thing I think.
2D sketches are rather generic; there is really nothing special about them, and I would guess that just about any 2D sketch from any program could be imported into Solidworks and used successfully.
Makes me wonder if folks are just not aware that they can import 2D sketches into their sketch plane? or whether that feature is available in programs other than Solidworks?

I guess I disagree. Importing 2D from another program, at least for the normal 3D workflow is not normal. It is abnormal. Can it be done? Yes. The program makes provisions for that as you have demonstrated. But I bet if you asked any of the 3D developers is that the way they recommend or intended, I would be shocked if 1% answered yes.

Its analogous to the example I mentioned previously. Can SW import a mesh file from another program or 3D scanner app? Yes. It allows you to manipulate the mesh, extract portions to make surfaces, convert to solid, export it out via various extension formats. That gives SW more utility & power to people that may encounter these situations during normal work. But SW is not a 3D mesh modeler per se like other programs that specialize in this domain. Are SW users aware it can import mesh & has this functionality? Maybe, maybe not. Its not like SW is hiding it, why would they? Depends on how familiar you want to be with your app & what you are trying to do with it.

Solidworks 3D also makes Draftsight 2D. Never have I see a recommendation to use DS to make 2D sketches & import into SW like you are doing. IMO if there was another angle to extract even more $ by recommending DS it as a complimentary tool in this regard, even on questionable grounds, surely they would, but they don't. AutoDesk makes 3D Inventor & 3D Fusion-360. Similarly I have never seen a recommendation to use whatever legacy/2D program is out there vs the built in sketch tools.

One of the (many actually) important points you missing is: importing a 2D sketch & developing a solid part from that only takes you so far in 3D modelling. I'll say the 30 yard line of SW capability. Sooner or later you will be forced to sketch referencing the features themselves. By that I mean surfaces, planes combinations of part features, planes offsetting a surface, combinations of axis, points, tangencies, even curved surfaces... literally hundreds of permutations that come about in parts & assemblies. Now what? How do you get all that underlying geometry reference back to a 2D program to make a sketch, which BTW is entirely disconnected from your 3D model. In other words if you make one minor change to a part feature way up the tree & all the other features change as a function of that change, the whole importation process blows up.

So its working for now. And if you're happy then I'm happy. But I would never go so far as to recommend that process to anyone.

 

[Richard Hed]

Yes, this is a valid point.

But I would guess a number of folks come from the Autocad world, but that is just my guess.

Should we do a poll? ie "Who has a 3D program and a separate 2D program on their computer?".


POLL #1:
Post here if you have a 3D program, and a separate 2D program such as AutoCad or similar program on your computer. (Yes/No).
We will do a headcount.

POLL #2:
Post here if you have ever copied a 2D sketch from a 2D program and pasted it onto a sketch plane in a 3D program. (Yes/No).

POLL #3:
Post here if you were aware that you could copy a 2D sketch from a 2D program and pasted it onto a sketch plane in a 3D program. (Yes/No).

.

If I answer your question, will I become PRESIDENT? I have AutoCAD 2004i Arachitectureal. It is both 2D and 3D. I never use the 2d except to draw for the extrusions. I have, however, used a lot of 2D programs, particularly for people who wanted thier work to be 2D?! Hard to believe. I have used Inventer, which I REALLY like but it is an old copy and will not run on the modern computers. I have also used Solidworks and others. Truly--3Ds are superior in every way, every day. Even as weak as Alibre Atom is, it is sstill superior to any cheap 2D program.

 

[johnmcc69]

Owning 2 different (2D/3D) cad programs is probably more common than you think. As a "Contractor", you may have clients who only work in 2D, & give you "roughed in" mechanical designs to finish in your 3D package. Another example is, I started in 2D ACAD & had that. As the trend progressed to 3D design, "customers" started using 3D & that requires you to upgrade. (It sounds like your example Pat). I still have both ACAD & Pro-E on my CAD computer (although I think I'm screwed now that it has puked it's hard drive & can't find my original install disc's after moving.)

I did use ACAD for "tracing" old prints of engines to use in my 3D designs though, for establishing sizes & scale, (much like Jason uses in his "trace" function" in Alibre), but I NEVER imported the data from that. I import the .jpg .bmp, whatever..). Once in ACAD, it comes in at some weird scale (& I don't even care what it is.), & then I re-scale it there, using, guess what? The SCALE command. I usually have a dimension on the drawing I can use as a reference, say a flywheel Dia. of 6", & use that. I actually pick a couple of points (Very close to dimensioning the flywheel image) & "dimension" the image. It will give me some crazy dimension (again, I don't care). The dimension might be something like 122. 6897" (OR MM, units are units, dimensions are exaggerated). I then use the "scale" command" in ACAD, you have a couple options here, "Scale Factor" or "Reference", choose "Reference", it will ask you for the "Reference" dimension & you will enter 122.6897", it will then ask you for a dimension, you will enter 6" & next thing you know the WHOLE drawing will scale itself based around the 6" flywheel scale you entered. Pretty cool huh?-But, like I said, I DON'T import any of this into my 3D CAD. I will return to my 2D image & get some more dimensions & usually round them off to a usable Dim. -As a side note, I have (2) computer monitors that I can bounce between, with both programs open & this makes this pretty easy.

TBC...

As an example, I created these drawings using my methods explained above...
https://www.homemodelenginemachinist.com/threads/stuart-turner-compressor.32535/page-2#post-351373
John

 

[GreenTwin]

One of the (many actually) important points you missing is: importing a 2D sketch & developing a solid part from that only takes you so far in 3D modelling. I'll say the 30 yard line of SW capability. Sooner or later you will be forced to sketch referencing the features themselves. By that I mean surfaces, planes combinations of part features, planes offsetting a surface, combinations of axis, points, tangencies, even curved surfaces... literally hundreds of permutations that come about in parts & assemblies. Now what? How do you get all that underlying geometry reference back to a 2D program to make a sketch, which BTW is entirely disconnected from your 3D model. In other words if you make one minor change to a part feature way up the tree & all the other features change as a function of that change, the whole importation process blows up.

No nothing blows up.
There seems to be a general misunderstanding about this.
The 3D program has no idea if you have imported a sketch from AutoCad or elsewhere, or whether the sketch was created in Solidworks.
It is just lines, endpoints, lengths and angles, in the Solidworks database.
There is nothing in the SW database that says "this line was drawn in AutoCad".
A line is a line.

Any changes that need to be made to a sketch can be made directly to the sketch in Solidworks.
Sometimes I erase a sketch in Solidworks, and copy and paste an entirely new revised sketch in its place. No problems doing this.

There is no reference back to a 2D program; I keep hearing this over and over, and it is false.

You make the initial sketch in Autocad, copy and paste it into Solidworks, and extrude your shape.
You can do this for every sketch you add in the Solidworks model.
Any tweeking to the sketch can be done in Solidworks, or as I mentioned you can copy/paste over a previously copy/pasted sketch.

Solidworks does not know you are importing sketches instead of creating them in native Solidworks.
Solidworks does not act any differently if you import all your sketches or create all of your sketches in Solidworks.

With all due respect, clearly you have no concept of what is happening with the sketch import feature, or what is happening in Solidworks with or without imported sketches.
Jason keeps repeating the same false things too, so clearly he is not understanding the import process or how it works either.

I mean, it is one thing to not recommend something because you fully understand how it works, but to not recommend something, and then make a series of false statements, is not really a recommendation based on facts.

No slights are intended towards anyone, but I can see this conversation is getting nowhere, and there is no understanding of what I am doing with either AutoCad or Solidworks, or what the programs themselves are doing.

I am going to throw in the towel on this discussion; it appears hopeless.

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[GreenTwin]

But I would never go so far as to recommend that process to anyone.

But if you were using the process, and it was working exceptionally well for you, would you still say this?

I think you are saying this because you don't use it and are not familiar with how it works.

.