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

[GreenTwin]

I use snaps a lot in AutoCad, and with larger grips, it is very easy to snap to endpoint, midpoint, nearest, etc.

In Solidworks, the grips are tiny, and it is very difficult to tell if I am indeed snapping to some fixed point.

In Solidworks, I think the snap may be reflected in the small avatar, or it may be a color change on the endpoint, but at any rate it is very difficult for me to use snaps in Solidworks, and it shouldn't be that way.

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[GreenTwin]

I also use differing line colors (colors 1-9 mostly) extensively in sketches in Autocad.

I am not sure if I can do that with lines in a Solidworks sketch.

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[GreenTwin]

And Solidworks draws lines in blue, or I guess black if fully defined.

And the X,Y,X planes are also blue.

So when I draw a line with the planes on, which I often do, then one or more planes may be on edge, and thus show up as blue lines, which makes it really difficult to see the blue lines in the sketch.

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[Richard Hed]

You should write a book.

 

[GreenTwin]

I think I just did.

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[Bentwings]

turns out to be an incredibly long thread . I’m a mech engineer so I’ve been through quite a number of cad systems , each a little different. One thing that set me off working in the machine shop with already half a dozen cad programs behind me , the engineers up front would bring prints of sketches They may or may not have been fully dimensioned or even dim correctly. After rejecting a number of these I became a bad guy in the tool room some programs had auto dim in the drawin pages. I occasionally would take the new guys out to their work stations and show them where the different size drawing formats were then the programs that had auto dim I would show them how to at least make a more or less correct drawing if there were double dim I really didn’t care at least there were things that I could actually make I showed the how to build in tolerances so that they would come out right on the drawing format. They could edit the notes or text but that’s not correct if it’s laid out right the rol will be built in . In later years as cnc becam more popular and paperless shop became reality til became what the machines could make if something special was needed more clearance for example then design it into the part any additional tool was in the machine very close hole shaft fits fit example it’s a bit too complicated to explaine here but I think the level of experience already shown could figure it out Special finishes cold be none by notes or a simple phone call shop to engineering

As fo design I generally start from a raw material a square block for example I may have to bore a hole in it so sketch the block add a circle to a plane an extrude it through all or to a give depth make a drawing page add dim all and you have three views plus any others you need I leave radius and chamfers untill the last minute so to speak that way they don’t get in the way some time you might need them so you can create another feature so us them then delete them. You can go on a clean up mission when nearly done If you are working in a group things get complicated fast We usually had weekly or more often meeting to discuss and fix issues Newer cad systems have much better bills of material lists you usually don’t have to do much editing unless there are specialty parts of late it’s pretty easy to import just about anything and it drops right in So things you can edit directly others you might have to explode an assembly the old manual bills of material were really tough to maintain . I transferred a number of machines from 20 year old board drawings to solid models . I’m glad that’s over .

Anyway good thread ther I a lot of info here.
My beam design was not going well, and I was unhappy with it.

Sometimes you have to see what does not work well in order to think of a better approach.

I could have drawn a more simple beam more easily, but I was trying to match the original 1840's Mississipi beam drawing exactly.


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[Jasonb]

You can set the colours in most CAD programmes to various preset schemes or customise to taste as well as how sensative the snaps are.

Again by using a snap you are really constraining/relating one point to another even if you don't realise it

As for drawing angled lines I'll drag the mouse to approx angle and type in the angle rather than clicking at the end of the line, faster than doing a vertical and then pulling it over. If it's a common angle then Alibre will sense that and fill in the angle for you so you then just press enter to confirm, typically picks up multiples of 30 and 45deg

As for threads that got a mention somewhere, agree no need to show the physical appearance if you don't want to but often better to correctly detail the hole at the design stage with a thread rather than just a simple hole. Reason being that when you come to produce your 2D working drawings it will show the thread as double lines not a single line that you get with a plain hole and it will also place a thread call out onto the drawing so you don't have to remember what thread you used when the part was designed months ago and have to look back and then add the description as a note.

 

[GreenTwin]

Jason makes a good point about how you want your 2D drawings to end up visually, with the double-lined threaded hole (although I don't use that feature, but perhaps should).

This applies to adding fillets too.
Sometimes I create the 2D drawings before I add the fillets, or sometimes I toggle the fillets off, else you will get a very busy 2D drawing.

With AutoCad, I have programmed the keyboard with shortcut keys, most of which are centered on the left side of the keyboard within reach or under the left index finger. I can basically quadruple (or better) my 2D CAD speed by using the mouse and the left hand, with the left index finger or far left finger being used to start the most common commands, such as line, move, rotate, copy, offset, mirror, save, trim, delete, block, matchproperty.

Solidworks also has programmable shortcut keys, but I don't have that set up yet.

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[petertha]

The best way to make holes in SW is use their vast built in menu. Rather than drawing a 0.250" circle in a sketch & extruded cut to some depth, pick exactly what you want. A 1/4-20TPI threaded hole is just one button click from a drop down menu, just defined by the center point & surface. It reflects the correct pilot hole ID, the cone of the drill (vs a cylindrical end), counterbore fastener head depth if toggled, displayed with/without cosmetic threads length.... Come drawing time, just click the hole callout feature & it puts all the relevant machining information attached to an arrow.

Oops, made a mistake, its supposed to be 8-32 not 1/4-20. No problem. Simply select the hole in the model, reselect 8-32 & everything downstream (parts, drawings, assembly) updates accordingly. The menu includes threaded holes, dowel holes, nominal drills, number drills, metric/imperial....

 

[GreenTwin]

The best way to make holes in SW is use their vast built in menu. Rather than drawing a 0.250" circle in a sketch & extruded cut to some depth, pick exactly what you want. A 1/4-20TPI threaded hole is just one button click from a drop down menu, just defined by the center point & surface. It reflects the correct pilot hole ID, the cone of the drill (vs a cylindrical end), counterbore fastener head depth if toggled, displayed with/without cosmetic threads length.... Come drawing time, just click the hole callout feature & it puts all the relevant machining information attached to an arrow.

Oops, made a mistake, its supposed to be 8-32 not 1/4-20. No problem. Simply select the hole in the model, reselect 8-32 & everything downstream (parts, drawings, assembly) updates accordingly. The menu includes threaded holes, dowel holes, nominal drills, number drills, metric/imperial....

What is this feature called?, ie: which pulldown menu has it?

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[Jasonb]

In Alibre it;s called "Hole" hopefully Solidworks has something as simple.

There is a dropdown under Hole for external thread which again will use the ISO or whatevre drawing standard to show the external thread on a 2D working drawing as well as thread call out etc.

 

[GreenTwin]

Looks like in SW, it is Features, Hole, and then options for Simple, or Hole Wizard.

The Simple is just a hole, so no different than drawing a circle and extruding a cut, it would seem, but perhaps saves a step.

The hole wizard gives options for various countersink types.
I don't notice the hole wizard drawing any threads.
The hole wizard does allow a selection of bolt sizes, and you can add clearance, but I don't think it is drawing the tap drill size.

I actually draw the tap drill size, I think, or perhaps not.

I use clearance holes on cylinder heads, and tap holes in the cylinder flange, but I can't recall what I show in a 3D model.
I will have to go look at a few 3D models.

The threads just get too busy on the 2D drawing, so I don't show those.

I do call out either clearance hole and size, or tap drill size on the 2D drawings.

If the hole had a countersink, you could save a few steps with the hole wizard, maybe, since the hole wizard adds the countersink automatically to the hole.

There are a lot of commands and features in Solidworks that I don't use.
It is probably safe to say I am a minimalist Solidworks user; I only use what is absolutely necessary to develop the model; no bells and whistles.

I do use features like molding, parting lines, and other tools on the foundry toolbar.

I guess it depends on how frequently I use a command, and how much work the command does, as to whether I will research the command and learn it. Sort of learn-on-demand, to keep from getting overwhelmed by trying to learn every command at once..

I have found that if I learn commands, but then never use them, I will forget those commands.
If I am creating a model, and need a method to do something, and I then find a command that will work, I will remember that command and when to use it.
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[Jasonb]

Pat here is a block, lets say we want two M6 tapped holes in it. On the left Ihave drawn a 5mm circle and extrude cut that helps I know the tapping drill size. On the right I have used the hole option and just clicked on M6.

Basic part does not look that different and you can see that the detailed hole is the correct 5mm tapping size so I did not have to look it up.

Alibre does have the option to show cosmetic threads, this can often be useful for those that find it hard to read 2D drawings

Where using the correct hole details at the design stage comes into it's own is when you come to produce 2D working drawings some time later. You can see the fully detailed one on the right is shown with the double lines so easy to see it is tapped and not just a plain hole. Alibre will also add the thread call out etc

If I was using the left hand option I would need to remember back to what tapping size I used for the intended thread and then type out the thread description etc

 

[Richard Hed]

Pat here is a block, lets say we want two M6 tapped holes in it. On the left Ihave drawn a 5mm circle and extrude cut that helps I know the tapping drill size. On the right I have used the hole option and just clicked on M6.

Basic part does not look that different and you can see that the detailed hole is the correct 5mm tapping size so I did not have to look it up.

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Alibre does have the option to show cosmetic threads, this can often be useful for those that find it hard to read 2D drawings

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Where using the correct hole details at the design stage comes into it's own is when you come to produce 2D working drawings some time later. You can see the fully detailed one on the right is shown with the double lines so easy to see it is tapped and not just a plain hole. Alibre will also add the thread call out etc

If I was using the left hand option I would need to remember back to what tapping size I used for the intended thread and then type out the thread description etc

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Are these features in Alibre Atom? I have never found them. Would sure like to have them.

 

[Jasonb]

No you don't get them with Atom or Home, just pro and expert.

 

[awake]

I can grab any line, drag it over, and no other line will move, because there are no relations (constraints) in Autocad.

If I create the same sketch on a 2D plane in Solidworks, the program automatically associates every line with the next lines drawn.
If I drag any line, it affects all previous lines, and will try to drag/stretch them too.
If I offset in SW in a sketch, it will offset every line I have previously drawn, not just the one line I have picked.

I don't know SW, but in the 2d sketcher for FreeCAD, you can do that - draw individual lines, each of which can be moved / offset individually.

The problem is, if the endpoints of those lines are not eventually joined (which is a type of constraint), then you will never be able to extrude a solid from them. Thus, the typical method is to draw, not a series of individual lines, but a complete shape - rectangle, octagon, etc. - and then position and size from there.

 

[Jasonb]

I said in the Cad Question thread that I would do a video as to why I use constraints and dimension items as I sketch them.

Video start s with what look like two identical parts that could be the covers for a steam engine valve chest, they have been extruded from a single sketch.

I then edit that sketch, from the start you will see that the cover on the top left is made up of black lines these show that all lines and circles are fully defind in regards to position and size. There are also a number of small icons showing the relationship of various parts, this can be toggled off if you feel it clutters the screen but that only makes them hidden from view not actually removing them. Compare that to the one bottom right which is all in red as nothing has a set length, angle, relation to another or position, the only constraint is that each line joins another at the corner as I could not have extruded it otherwise.

I then proceed to make alterations to the top left cover changle length, width , hole size and finally hole position. You can see it stays rectangular as I started the sketch using a rectangle tool than makes corners 90deg, sides parallel and equal to the opposite side. All four holes change size as I have an equal constraint on them and all four move as they are mirrored so changing the first will move the others the same amount.

Next I do the same to the bottom right and all hell brakes loose. Only one side changes length so I end up with a quadrilateral and then changing the width makes it even worse. Only one hole changes size and when I enter a position it only moves the one hole and not where it's wanted.

So Pat I can't see why you say DON'T use constraints and dimensions when they make managing your sketches so much more predictable. I suspect you are actually using constraints and dimensions but don't know it.

 

[petertha]

What is this feature called?, ie: which pulldown menu has it?

Looks like my reply is a bit late. Our first snow dump UGH. I'll post some pictures. Yes its in the features menu, not sketch.

 

[petertha]

Defining holes through the features menu the way I've shown has other down stream benefits. You can identify all the pertinent parameters that a machinist would require just by clicking on the hole call out, annotation tab in drawings. Its as easy as clicking an edge like when making a dimension.

But also if you have an array of holes, you can spit out an XY type drill table in the drawing using any arbitrary user defined datum point as 0,0. Very useful. You cant do this with hand drawn circle extruded cuts which are a regular design feature. Holes are kind of special attribute in SW.

 

[Bentwings]

it looks like the spell check editor destroyed my previous reply . When I first started drawing class I about 5-6 grade I had a lead screw to 2 d draw. I barely passed because I didn’t shade it correctly . Atvtge time there were had a dozen ways to spell drawing person al rediculous even then. When inhadvtongonback snd shade that screw I made up my mind there had to be a better way i hated “ drawing” class . I knew I wanted to be engineer but laying on the big drawing board all day really turned me off . I nearly changed to business law and economics in college . I may have made a bad choice there I probably be some rich politician now LOL I struggled through math physics and mechanics actually finishing up near top of the class. brag a little . Once I got to industry I ran into my first wire frame cad by today this is really primitive . It was nothing but electronic pencil after had a dozen upgrades the first 3D wire frame modeling came out you still had to make those dam drawings often the program did not allow using “ proper” drawing standards “. I don’t remember the the first actual solid modeling cad . It was quite a change . When I found that it automatically created drawings with any view presentation I was starting to be really happy the advent of a tool box that had every fastener and hole with threads already modeled so you could just drop them in then the “ drawing” called them out and the bill of materials auto updated things began to be enjoyable I modeled that old lead screw complete with correct threads, then shaded it so it looked like wood steel as UMI bum even titanium .

So today there are still a few that are even older than I that just can’t let go of old school . It’s time for change guys and gals if you need your note pad for basic ideas fine then click “ new “ and select a plane to start your new solid model you migh have to do a little reading maybe purchase a book . Just pretend you are the machine making something you can add or subtract material change material Shade it to your hearts content I could be really bad and just say delete 2d from your vocabulary but I’ll leave it out solid modeling is here to stay . Once you create the solid model you can make it realistic by sending it to your 3D printer I haven’t tried a 3D printed letter yet but I will eventually Email is too easy excep for this dumb auto spel check as many emails and replysvit still doesn’t let me spell my name correctly so you will see strange things like commas dots etc in my name

By, ron
It is quite interesting to compare notes with others using 3D programs to design model engines.

I got interested in 3D watching Brian Rupnow do it way back in 2011, and it was just something I had to learn.

I am glad everyone is sharing their ideas on what all the options are with 3D.

I learn a lot from every one of these discussions.
The feedback is very valuable to me.

I have always suspected that I am just touching the surface of what Solidworks is capable of doing.

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It is quite interesting to compare notes with others using 3D programs to design model engines.

I got interested in 3D watching Brian Rupnow do it way back in 2011, and it was just something I had to learn.

I am glad everyone is sharing their ideas on what all the options are with 3D.

I learn a lot from every one of these discussions.
The feedback is very valuable to me.

I have always suspected that I am just touching the surface of what Solidworks is capable of doing.

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