Bernay 3D Tutorial

[JorgensenSteam]

Valve rod.

 

[JorgensenSteam]

And that is as far as I got with the Bernay 3D model.

Note:
This Bernay was designed and built in 2004, and should not be confused with the Bernay that was published in Live Steam in 2006.

This is a larger Bernay, and I think a better design IMHO.

 

[petertha]

Neat.
I'm guessing this is Solidworks, right? Dumb question, but assuming your SW default colors re: black= fully defined & blue=not full defined, is there a particular reason why most of the successive operations in the screen pics are not fully defined by hard dimensions etc? Do you leave this to the end, or?

 

[JorgensenSteam]

I just started using Solidworks last year, and am self-taught, so I have no idea as to the answer to your question, or even what it means.

I just draw em, I don't think about much.

 

[ausdier]

Hi UNI.
I think what petertha is saying is that if you just draw a line on the page it starts off as blue.
Then if you define it by giving it coordinates for each end it will be defined.
This can be done in a range of ways.
1 if you start the line frome a known point to another known point then it automatically gets defined.
2 if you start from a known point and you see the symbols for either vertical or horizontal when you finish the line and then give it a length (dimension it) it will then be defined.
3 once again if you start from a known point and go at an angle you will also have to incorperate the angle desired to make it constrainted.
Basically to change the line or curve from blue to black it needs to know X and Y and sometimes Z where all the geomitry of the line are.
What may be happening is that you may be drawing the 2D drawing and dimensioning it then deleting the dimension when it is all right to either hide the dimension or to declutter the drawing, this will then cause the line to change back to blue as they are correct but not defined?
I hope this is some what helpfull to everyone.

 

[petertha]

I just started using Solidworks last year, and am self-taught, so I have no idea as to the answer to your question, or even what it means. I just draw em, I don't think about much.

OK. Well Im not that much further ahead, but I'll offer a few comments, if for no other reason than more fully utilize the program & avoiding potential pain down the road.

Think of the blue color state (ie not fully defined) as 'kind of variable' in your mind right now. The shapes you have drawn are still available to move or maniplulate in some fashion because some combination of [dimensions, angles, relations between other geometry or elements... etc.] allows this. Thats probably why SW calls it 'sketch' mode. To prove this to yourself, just grab something blue with your mouse, a corner or a line segment... and drag or nudge it. More than likely something will give or stretch or distort.

So if you thought you were 'done', thats not good. While still blue/undefined, you can inadvertantly mess it up. Then, the more add-on features you build on top of successive sketches (like bosses or holes or whatever) that depend on this preceeding or underying sketch geometry, the more deeply nested a problem can be. And that can get ugly in a hurry.

On the other hand, black (fully defined) means its mathematically 'locked down'. That means every element is known relative to every other element plus the datum. Of course you can always change a defined dimension or angle or relation (ex click change 5.0" to 4.5" or 10 deg to 15 deg). Black means its internally 'good to go' for subsequent operations & this is considered best practice.

Just getting into SW, this undefined/defined business seems like an extra step, especially compared to classic 2D cad packages where you just draw & the software pays less attention to the details. But actually, fully defined geometry is the only way it can internally solve most any subsequent 3D features like fillets & drafts & surfaces etc. Plus its a powerful safeguard against un-solvable & bad geometry issues. If you've ever had the pleasure of 3D software that 'blows up' unexpectantly & all you wanted was a simple fillet & you have no idea why, the SW workflow is a welcome friend.

There are some special situations where sketches are left undefined (or partially undefined) but thats kind of a differnt purpose. 'Try & make everything black' is the preferred route.

Hope this laymans explanation helps.

 

[JorgensenSteam]

That is an interesting note on using Solidworks.

Since the number of commands in all the various parts of SW is so vast, I started with drawing very simple shapes with simple commands.

I have progressed into some complex engines (some samples here http://www.homemodelenginemachinist.com/index.php?topic=14098.30

I guess ignorance can be bliss, since I have never fully defined anything, and it has not caused any apparent problems. I generally draw a horizontal and vertical line, and then offset them to the size I want. I don't use the rectangle tool because offsetting lines is faster for me.

The constraints really get in the way of what I am trying to do most of the time.
Occasionally they are useful, but they cause so much trouble that I have tried to turn them off altogether.

I guess for a feature to be useful/helpful, it has to work for what you are specifically applying it to, and features are not a "one size fits all" type thing.

I still use Autocad for many of the more complex sketches, and then import them into SW. In my opinion, Autocad has much better grips/snaps, and like I said, for what I do, almost always the constraints work against me big time in SW.

I have seen comments that sketching and using constraints are great features in SW, but I don't see many modeling what I model, so I am not sure if the comparison is fair.

I guess in my mind, the program records all of the sketch dimensions, it has to in order to define the object, so it seems totally redundant to add dimensions to something that is already defined.

I like to keep it as simple as possible, since SW is complex enough as it is.
My philosophy is "less is more".

It is good to know about "defined" lines/shapes, I am sure I don't fully understand it.

Here is another model I have been working on recently.
Again, nothing is defined in this model.
(This is a Stanley 20hp auto engine, modeled at full scale).