2D design

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Neat engine.
Do you ever go back & try & remedy these warnings? Why are they there?
 

Attachments

  • EDT-2022-10-28 11.55.10 PM.jpg
    EDT-2022-10-28 11.55.10 PM.jpg
    54.2 KB · Views: 4
My 2D drawings are full of every kind of sketch you can imagine, and I leave a papertrail as the design progressed.
This is what is lost if you only use a 3D program, the chalkboard sketching pad thing.

Not so, you can do as many 2D sketches in a 3D program as you want and simply leave them as that. Not all sketches then have to be turned into features
 
Yes and you don't have to restrict yourself to one plane, sketches could be on several or sketched onto the face of a part. Then they are all there in one place so easy to go back and look at them.

Could even extrude those sketches but suppress the extrusion so it does not show on the actual 3D part.

"I try to start the base sketch with its center at the X, Y origin.
Then I can mirror around the X,Y,Z planes.

If you just randomly start a sketch in space somewhere, you lose a lot of mirroring function."


Yes that is constraining it to an axis/plane/point which is what has been discussed before.
 
If you just randomly start a sketch in space somewhere, you lose a lot of mirroring function.
Not quite sure what you are referring to. I made an axis out in space (unrelated to the origin), drew a random shape to the right of it & used the mirror function. As you can see it works. Just a guess, but when secondary operations appears to fail, you likely have a self-induced geometry problem. SW provides several tools to help diagnose them, but we have discussed all this before.
 

Attachments

  • SNAG-2022-10-31 8.16.05 AM.jpg
    SNAG-2022-10-31 8.16.05 AM.jpg
    13.1 KB · Views: 3
  • SNAG-2022-10-31 8.16.40 AM.jpg
    SNAG-2022-10-31 8.16.40 AM.jpg
    16.7 KB · Views: 2
  • SNAG-2022-10-31 8.16.50 AM.jpg
    SNAG-2022-10-31 8.16.50 AM.jpg
    17.7 KB · Views: 2
Infact you don't even need an axis, provided one side of the random shape is straight you can mirror it about that same as you can revolve it
 
I have used Autocad2004 for a long time, but I have not noticed this trick.
I will have to try it.

Autocad2004 will actually do things in 3D, but I don't know how to control the Z plane, so I don't use it.

There are a lot of tricks in Autocad, such as when you rotate an object, if you use REFERENCE, you can snap it exactly to a line that is at some defined angle.
I use this feature all the time.

Edit:
I tried the SCALE, REFERENCE feature.
I am not sure exactly what I did.
I drew a line, did SCALE, it asked for reference length, I typed in 1, it asked for new length, I typed in 2.

But if you pick the line and LIST it, it says length is 59.2114.

Normally I import a raster image of an engine I want to create, draw a circle over the flywheel perimeter, and pick LIST.
If I know I want the engine to have a 12" diameter flywheel, and say the list command says the raster image flywheel diameter is 24, then I scale the entire raster image and the circle I drew by a factor of 0.5.

When you are drawing over raster images in Autocad, you can sometimes end up with your lines behind the raster image.
I do a window that picks only the lines, move them over any distance, and hit UNDO, and that will move your lines back on top of the raster image.

Seems like the SCALE, REFERENCE feature could give you a dimension that you don't necessary want or anticipate.

I always work in absolute terms, ie: if the original engine had a 4" bore and a 5" stroke, then that is what I draw my geometry sketches to match in Autocad. Once I get the entire engine design complete, I scale it to whatever scale model size I want.

An alternative approach is to draw a model at its scaled dimensions, which will save you some time, but is only good for one scale factor. So you may draw a 1/2" as a 1/4" bolt in your scale model, and draw a 24" flywheel at 12".
Your crankshaft can be rounded to the nearest standard shaft size.

.
I have found it helps to place a 1/64's scale near the part I want to trace before I import into Acad to help when I scale to the size I want.😁
 
You lose the ability to mirror symmetrically around the standard top, front, side planes, which is very convenient.
That's because Mirror function within Sketch mode does not work that way in SW. You first specify a plane to sketch, then draw some sketch entities, then Mirror them within Sketch mode (my example). Sketch level SW does not know about other planes, primary or created ones.

If you exit the 1/2 sketch & attempt to Mirror it within the Feature mode, you can see Mirror menu function is greyed out. Mirror within Feature menu is intended for 3D model elements & features. Maybe that's the source of confusion?

Perhaps you are attempting to replicate a 2D ACAD workflow here, but not really sure. So its not really a 'lost ability' in SW, it was never there to begin with. By design.
 

Attachments

  • EDT-2022-10-31 5.26.06 PM.jpg
    EDT-2022-10-31 5.26.06 PM.jpg
    55 KB · Views: 2
  • EDT-2022-10-31 5.27.37 PM.jpg
    EDT-2022-10-31 5.27.37 PM.jpg
    136.4 KB · Views: 3
Last edited:
Mirrored 3D body example
 

Attachments

  • EDT-2022-10-31 5.39.02 PM.jpg
    EDT-2022-10-31 5.39.02 PM.jpg
    57.1 KB · Views: 2
  • EDT-2022-10-31 5.39.54 PM.jpg
    EDT-2022-10-31 5.39.54 PM.jpg
    66 KB · Views: 2
  • EDT-2022-10-31 5.40.44 PM.jpg
    EDT-2022-10-31 5.40.44 PM.jpg
    53.1 KB · Views: 2
I started using AutoCad for 2D drawings 33 years ago.
Prior to that, we hand-drew all of our drawings on vellum, which is cotton-based paper (very durable).

I still use Autocad 2004 every day to make a living.

I have never found a better 2D program than Autocad 2004.
They refined it over years, and it is rock solid.

The early versions of Autocad were terrible about locking up randomly.

.
I use Autocad 2000 it installed on my new Laptop using Windows 11 64 bit.
I also have Autocad 95 install too. It works great on Windows 11 too. It does take a new 32 bit installer for both witch I can email if any needs the installer.

Dave
 
I always try to keep a part somehow located at the X,Y,Z point, and not just randomly located in space.

And how do you do that? Give it a value as to how far it is to the point, allow the software to snap to that point or something else.
 
Back
Top