3D cad question

[Gordon]

I have been using 2D cad for 25+ years and I have tried to use 3D programs (Fusion 360 and Freecad) and I just cannot get used to the data entry. With my 2D program I can enter X & Y values and it enters that value. For instance if I want to draw a rectangle I could enter 3,0 then 0,4 then -3,0 then 0,-4 and end and I would have a 3 x 4 rectangle. With the 3D programs it seems like you make a rectangle about the right size and in about the right location and then move it and resize it. Are there any 3D programs which have a similar data entry system?

My usage is hobby so an expensive program is not going to be an option. FYI my current 2D program is Visual Cadd.

Thanks

 

[kuhncw]

Gordon,

I'm a long time Visual Cadd user also and still use it. Sometimes 2D is quicker depending on the job. For 3D, I use Alibre. Rather than enter specific points when sketching, it works well for me to rough in the shape, then use the dimension tool to specify length, diameter, angle, etc. This is essentially what you described and does not answer your question regarding other 3D packages, but for me eliminates the need to key in X and Y values.

Chuck

 

[Charles Lamont]

I suggest you try Onshape. You can use it for free (so long as you don't mind your documents being publicly accessible), and there is nothing to download. It works in your browser (Chrome, Firefox, Safari, Edge). There are extensive tutorials, help, and a forum for support. It has a nicer user interface design than most of the competition. Some of the concepts and ways of working in 3D CAD may be alien to a new user, but you need to keep an open mind rather than trying to bend it to your ideas. The only requirement is a decent broadband connection. A reasonable GPU helps, but I am quite satisfactorily using an originally well specified desktop that is now getting on for ten years old.

I have been using Onshape for more than 6 years now, and only yesterday I found a video tutorial that explained how to do something that had me foxed for a while. "Oh, I see, I didn't know you could do that." I have also used Autosketch for 20-25 years for 2D, and I still use it extensively.

 

[Richard Hed]

I have been using 2D cad for 25+ years and I have tried to use 3D programs (Fusion 360 and Freecad) and I just cannot get used to the data entry. With my 2D program I can enter X & Y values and it enters that value. For instance if I want to draw a rectangle I could enter 3,0 then 0,4 then -3,0 then 0,-4 and end and I would have a 3 x 4 rectangle. With the 3D programs it seems like you make a rectangle about the right size and in about the right location and then move it and resize it. Are there any 3D programs which have a similar data entry system?

My usage is hobby so an expensive program is not going to be an option. FYI my current 2D program is Visual Cadd.

Thanks

I'm telling you, Alibre Atom 3D is very easy to use. Altho', it took me two tries to figure out how it workt,cause it doesn't work like other CADs. But once I figured it out, it is very nice, that is, it is very nice for the price and power. It doesn't have everything, but it has 99% of what I need for a 2Ds and 3Ds. It's also free to try for a month.

The instruction manual is too simplistic, however, it is not difficult to follow along. I understand there are user forums too. It is 100$ for a perpetual liscense and NO dog-damn clod business!

If you used this to the point of understanding it, you would be very happy that you persisted. It makes excellent 2Ds too. I export them pdfs if I want a print. And that is an excellent way to to store them. Just for funzies, I'll put one here:

PS, that odd angle has been fixt, it is supposed to be 60deg, but I didn't know I would be sending it out for peeps to see.

 

[Jasonb]

I don't use fusion a lot to draw but it's quite easy to dimension the rectangle as you draw it.

Select the rectangle icon, click approx where you want it to start and drag, Don't click again but you will see one of the dragged dimensions highlighted in blue so just type the dimension you want that side to be eg 3. Then hit the tab button and the other dimension is highlighted, again just enter the length of that edge eg 0.4. And there you have the rectangle dimensioned to what you wanted.

Position wise, some use snap or you can simply double click a corner and a box comes up to enter the co-ordinates. You can also do other things like make it symmetrical about one or two axis which is far more useful than positioning a corner. More so as you edit a part as when you change that 3 to 23.500 it will move equally about the ctr line

It's just a slightly different sequence but essentially you enter the same number of positions/dimensions just in a different order.

 

[Gordon]

Alibre seems to be a popular choice for hobby users. There is a 30 day trial so I may give that a try. I do like the fact that it is not cloud based. It goes on my computer and only on my computer. I tried Fusion 360 until it was no longer free for hobby users. I also have a problem with Autodesk. As I said I use Visual Cadd which originally was Generic Cadd. Generic Cadd got too popular and was competing with Autocad so Autodesk bought it and killed it.

 

[Jasonb]

F360 is still free for non commercial use (under $1000 turnover) and I use it for the CAM

I design with Alibre and the sizing of rectangles is the same as I described above for F360

 

[kvom]

With SolidWorks I just draw a random-sized rectangle and then dimension each side afterwards.

 

[timo_gross]

When I did 2d (pencil, ruler, ink etc. in school ), a hinge would have been drawn all pieces together at the same time, even the door would be drawn at this point.
Similar to looking at it from one side and draw what you see. Then turn 90°, draw what you see, .. repeat 2nd time and then you had hopefully a drawing with 3 views.

I think 3d works better one step at a time.
For the hinge example I would "develop" one side of the hinge, then the other side of the hinge and a pin. The position of the three parts would be relative to each other rather than absolute. Finally the hinge is copied and moved to the door.

If the small parts are all treated as separate things their absolute positions are more based on the positions of the next bigger part.

I would have a 3 x 4 rectangle. With the 3D programs it seems like you make a rectangle about the right size and in about the right location.d

My usage is hobby so an expensive program is not going to be an option. FYI my current 2D program is Visual Cadd.

Thanks

Yes I think you make a 3x4 rectangle, the position in space will be dependent on the assembly position or some other part you already have.

I am not sure if that all makes sense.

It seems that keeping things structured and organized, then getting enough practice with assemble workflow are the big challenges.

Greetings Timo

p.s. Fusion 360 is not free, "Beware of Greeks bearing gifts "

 

[abby]

I think the question "what cad ?" is rather like "what lathe ?" everyone recommends their personal product as the best even though most have no experience of more than one or two different products.
I think it is fair to say that they all do the job , after a fashion , and it's a pity that the user interfaces do not stick to a standard that would make learning different systems easier.
I find that after spending several years becoming proficient with one product I have no inclination to learn a new set of rules for another.
As a Mac user the choice was restricted to around 4 products and after trying all available I settled with ViaCad from punch software , I have bought one upgrade since my first purchase and , like everyone else , I recommend it ! I had a myford ML7 which I thought was the best until I sold it and bought an EmcoMat7 , went back to Myford then sold that for a Boxford "A" which I now believe is better than most similar sized lathes.
Dan.

 

[Gordon]

OK Off to get the 30 day trial of Alibre. I watched to intro videos on the site and it looks pretty simple.

 

[GreenTwin]

I have used Autocad for 2D drawings for years, and learned Solidworks in 2011.

Some have said they really like the 2D part of Solidworks, but I hate it.
I generally draw my 2D sketches in Autocad, and then import them into Solidworks.

If I had to use the 2D part of Solidworks to run a business, I would go broke.

I suspect they made the 2D part of Solidworks different from Autocad to avoid patent conflicts, but doing it different than Autocad is not a good thing, as far as how I use 2D.

Pat J

 

[Richard Hed]

I think the question "what cad ?" is rather like "what lathe ?" everyone recommends their personal product as the best even though most have no experience of more than one or two different products.
I think it is fair to say that they all do the job , after a fashion , and it's a pity that the user interfaces do not stick to a standard that would make learning different systems easier.
I find that after spending several years becoming proficient with one product I have no inclination to learn a new set of rules for another.
As a Mac user the choice was restricted to around 4 products and after trying all available I settled with ViaCad from punch software , I have bought one upgrade since my first purchase and , like everyone else , I recommend it ! I had a myford ML7 which I thought was the best until I sold it and bought an EmcoMat7 , went back to Myford then sold that for a Boxford "A" which I now believe is better than most similar sized lathes.
Dan.

I've used about 6-7 different CADs, I also taught CAD for 3 years. The best ones IMNSHO are the "ground up 3D CADs", that is, ones that were programmed from the beginning as 3D. Notably, AutoCAD became thee goto CAD and it started out as 2D. Eventually they were forced to 3D but it was jusst an add on to their 2D program. At first it was simply awful, but the eventually corrected it to some degree. The AutoCAD I have now is the most powerful CAD I have but dimensioning is hell. My copy is AutoCAD Architectural 2004i. So it may be way out of date.

We all know Pro-e, Solid Works, edge, and Inventor are all easy to use, easier than 2D, actually. But they all cost my wife's arm and two legs, and my dogs ears thrown in. I am an advocate of Alibre Atom and they haven't paid me for advertising for them, which I suppose, they should./ But they ARE cheap (100$) and it does a lot for that amount.

 

[Richard Hed]

OK Off to get the 30 day trial of Alibre. I watched to intro videos on the site and it looks pretty simple.

If you needs some help, just holler. Alibre IS, indeed, a bit different conceptually but once I got the concept down with a little practice, it became easy and is now my preferred CAD./ The hardest lesson for me to learn was that when STARTING a dwg, you have to click on one of the 3 2D drawing planes (X-Y, Y-Z, X-Z). That confuzed me something awful.

 

[Brian Rupnow]

Gordon--I worked on a drafting board for 33 years, then learned to use AutoCAD 14. I used AutoCAD 14 (2D )for three years, then changed over to Solidworks 3D. I paid about $6500 for my Solidworks license, but as I understand it there is a plan in USA for veterans to get a license for less than $100 American. Basically, in Solidworks you open a sketch, draw something close to the shape you want, dimension it to "lock in" the value then extrude it into the third dimension. It's probably not as simple as I make it sound, but I've used it for 20 years now and find it very user friendly.---Brian

 

[GreenTwin]

The hardest lesson for me to learn was that when STARTING a dwg, you have to click on one of the 3 2D drawing planes (X-Y, Y-Z, X-Z). That confuzed me something awful.

Yep, that part threw me for a while.
Some programs start on the front plane automaticaly, and that was confusing too.
The entire concept of getting on and off a plane was nothing like 2D CAD where you are always on the XY plane only..

Basically, in Solidworks you open a sketch, draw something close to the shape you want, dimension it to "lock in" the value

I have heard about constraints, and locking in dimensions and such, and have heard the statement that this MUST be done.

I have been using Solidworks since 2011, and I have never used constraints or dimensions, and so my thoughts are if you don't need a function, don't use it.
I don't have any problems with my 3D models as a result of not constraining or dimensioning them; I mean things don't just change themselves due to lack of dimensions or restraints.
If I were using Solidworks to build an oil refinery or something, I would consider constraints/dimensions.

And if I used Solidworks every day for work projects like Brian does/did, I would pay more attention to constraints/dimensions.
Sometimes Solidworks adds a dimension automatically, and I intentionally delete those every time they pop up.
I actually find constraints and dimensions totally counterproductive in 3D. They very much get in my way.
Of course you have to dimension the 2D drawings that are extracted from 3D models.

As I understand it, if you want to get sophisticated, you can link dimensions into a spreadsheet type affair, and then you can change cells in a spreadsheet, to change things. I have never used the spreadsheet option.
.

 

[petertha]

I have heard about constraints, and locking in dimensions and such, and have heard the statement that this MUST be done.
I have been using Solidworks since 2011, and I have never used constraints or dimensions, and so my thoughts are if you don't need a function, don't use it.
I don't have any problems with my 3D models as a result of not constraining or dimensioning them; I mean things don't just change themselves due to lack of dimensions or restraints.

Please don't take this the wrong way, but I'm actually surprised you have not had an issue yet. Its a bad habit & you are basically short changing yourself of a powerful SW feature by not fully defining a sketch before proceeding to the next part feature. By that I mean dimensioning lines, arcs, angles etc. & specifying their relationships, vertical, horizontal, perpendicular whatever. Think about a simple example. You quickly draw a line from left to right, the mouse is a bit skittish today, looks about right on the screen, but its actually 1.234 deg (not zero). You are used to seeing undefined blue lines, not defined black lines so you carry on. This sketch becomes the outline of an extrusion. SW still does not complain, it just does the best it can. But that error (which it is) is imbedded in your parametric part tree 20, 50, 100... subsequent features deep depending on the part complexity. Then the part becomes part of an assembly & you want to mate this supposedly 'good' edge to another part surface edge. Guess what, now the entire assembly is out of whack. Now maybe holes do line up & the lid does not sit square to the box... that kind of thing. ie. cascading issues that root back to that single oversight.

But OTOH if you take the time to ensure each drawing is completely defined, which SW tells you as the lines turn black, you eliminate escalating issues right at the source, the sketch. Debugging faulty geometry of solids that don't close or wont fillet or any number of issues is almost always related to this. No its not strictly required & there are many ways to skin the cat. But fully defining is considered good practice unless there is an otherwise good reason for omitting it, usually temporarily But that's another topic.

It also forces you to think through a sketch, what is called design intent. Its not a flakey concept. You may have a legitimate reason to dimension A,B,C & let SW calculate D to become fully defined. In a different part it may make sense to define A,B,D & have SW calculate C. You are in the drivers seat. But again, leaving them all undefined is basically leaving your design flapping in the wind so to speak.

 

[petertha]

As I understand it, if you want to get sophisticated, you can link dimensions into a spreadsheet type affair, and then you can change cells in a spreadsheet, to change things. I have never used the spreadsheet option.

That's called design tables, another super powerful feature.

Example-1. I design or download a 3D model of a cap screw, say M3x10mm. Obviously the length is a dimension within the part file. But I want a library of 27 cap screws starting at 2mm up to... you get the idea. Design table to the rescue. Use the wizard to build a design table, it shows default length 10mm. Use excel to just make new rows with defined incrementing lengths, 2,3,4,5... Boom done. You now have an M3 bolt library within that single part file. Come assembly time just drop in the appropriate length selected from a drop down configuration table. Modify later if that makes sense. This also cascades to the drawings of course.

Example-2. You have some kind of box for your beautiful castings. Its 4"x6". You have spent time making a whole bunch of features in that design. You want 3 more progressive sizes, 6x8, 8x12 & 10x14. Same deal. This time the design table would include those 2 (length x width) dimensions & generate 4 part variations (what SW calls configurations). You now have related 4 parts in a few seconds as opposed to creating duplicate files & just tweaking those dimensions.

This is just scratching the surface with many other possibilities, but just to get you thinking.

 

[GreenTwin]

Please don't take this the wrong way, but I'm actually surprised you have not had an issue yet. Its a bad habit & you are basically short changing yourself of a powerful SW feature by not fully defining a sketch before proceeding to the next part feature. By that I mean dimensioning lines, arcs, angles etc. & specifying their relationships, vertical, horizontal, perpendicular whatever. Think about a simple example. You quickly draw a line from left to right, the mouse is a bit skittish today, looks about right on the screen, but its actually 1.234 deg (not zero). You are used to seeing undefined blue lines, not defined black lines so you carry on. This sketch becomes the outline of an extrusion. SW still does not complain, it just does the best it can. But that error (which it is) is imbedded in your parametric part tree 20, 50, 100... subsequent features deep depending on the part complexity. Then the part becomes part of an assembly & you want to mate this supposedly 'good' edge to another part surface edge. Guess what, now the entire assembly is out of whack. Now maybe holes do line up & the lid does not sit square to the box... that kind of thing. ie. cascading issues that root back to that single oversight.

But OTOH if you take the time to ensure each drawing is completely defined, which SW tells you as the lines turn black, you eliminate escalating issues right at the source, the sketch. Debugging faulty geometry of solids that don't close or wont fillet or any number of issues is almost always related to this. No its not strictly required & there are many ways to skin the cat. But fully defining is considered good practice unless there is an otherwise good reason for omitting it, usually temporarily But that's another topic.

It also forces you to think through a sketch, what is called design intent. Its not a flakey concept. You may have a legitimate reason to dimension A,B,C & let SW calculate D to become fully defined. In a different part it may make sense to define A,B,D & have SW calculate C. You are in the drivers seat. But again, leaving them all undefined is basically leaving your design flapping in the wind so to speak.

Yes, I hear what you are saying, and when I tell people I have never dimensioned or constrained anything in any 3D model I have ever made, they are aghast with horror.
I guess ignorance is bliss, because I don't dimension, and I don't constrain, ever, and I have never had problems.

Granted I may be doing odd sort of stuff with 3D modeling.
I basically look at photos of old engines, and work from photos to develop one sketch and one part at a time, for a unique engine design.
My parts always mate correctly, and my assembly simulations run perfectly.
For a somewhat more othodox design (such as a commercial project design), I can see where one may want to be a bit more cautious.

If one has been taught that you must use constraints and dimensions always, and one has never tried anything else, then it may be ignorance of what one really needs or does not need when modeling an engine that is the driving force.
I have seen professional CAD guys doing dumb stuff because "That is what they taught us".
Some folks get their mind in a box, and can't see out of it (the old adage "you can't teach an old dog new tricks").

I am self-taught in both 2D CAD and 3D modeling.
I don't use paperspace in Autocad, and I get far better use and efficiency by not using paperspace in 2D CAD.
The veteran 2D autocad users are also aghast that I don't use paperspace, but I have a much better method (XCLIP).

For airport work, where the drawings are very long (like a runway that is a mile long), sometimes I have to resort to paperspace, but that is the only exception where I found paperspace to be more efficient than XCLIP.

And I put all of my 2D work drawings in a single file (per project), so when I open a project file, I see every drawing on the screen.
I have had up to 100 drawings in a single file in AutoCad 2D, and this is normal for me, and highly efficient, since I can copy/cut/paste across multiple sheets, and always have an overview of the entire project, with instant access to every sheet.
Most people are horrified at the thought of having 100 drawings in one drawing file, but I do what is efficient, not what is generally accepted by others. Efficiency is money, and I can show you the money.

So perhaps a hobby person could try 3D modeling while completely ignoring constraints and dimensions, and if that is not creating any problems, maybe you don't need to be spending time on those.

I am an extremely meticulous CAD and 3D person, and so perhaps constraints and dimensions would force a less meticulous person to avoid problems.
I can categorically say that dimensions and constraints are totally unnecessary in a complex 3D engine model, at least for the engines I have modeled. I have modeled some complex engines.

.

 

[GreenTwin]

One thing I have noticed that can be critical to engine design is where to begin the sketch/extrusion.

For instance when drawing a steam engine cylinder with flanges.
If you don't reference the flanges from the correct surface, then if you change the length of the cylinder, the flanges become too thick or thin.

If you extrude the flanges correctly, they will remain the same thickness regardless of changes to the cylinder length.

.