AutoCAD

Taking Another Look at 3D

22 Mar, 2012 By: Bill Fane

Learning Curve AutoCAD tutorial: FlatShot isn't the only way to generate 2D views from 3D models — try the Solid View, Solid Draw, and Solid Profile commands as well.


It was a warm and sunny December morning, just after Christmas. Captain LearnCurve, his gorgeous wife, their kids, and the grandkids were relaxing on the beach …

Wait a minute! You live in Vancouver! How could you be relaxing on the beach in December?

… relaxing on Po'olenalena Beach, in Hawaii.

Oh. That would explain it.

Suddenly an iPhone rang out and Rod, the Captain's son-in-law, answered it. It seemed that Rod and Joanne's offer had been accepted, and the two had only to trace out their signatures on the iPhone screen to become the proud owners of a condominium in Maui. That's it! This month's topic!

Huh?

Yes, it's obvious! Using your screen to display something else — 3D to 2D!

I say again, huh?

Don't worry, I'll explain. My previous Learning Curve column introduced one method for generating 2D working drawings from a 3D model. In it, we learned that the FlatShot command is a fast, simple way of producing flat 2D working views from a 3D model. After a bit of manipulation we were able to quickly generate 2D views of a 3D model.


The FlatShot command produces 2D views from a 3D model.



Now all you need to do is to add a few dimensions, some center lines, a title block, and you're done.

Unfortunately, FlatShot has a minor shortcoming: although it can generate hidden objects, it can't directly create a cross section. The good news is that each view is created as a block definition that can be edited. The blocks have strange names, along the lines of A$C7CBA1FF6.

For example, double-click on the front view to open the BlockEditor command and apply suitble section hatching. Close BlockEditor, and our front view now looks like this:


A FlatShot view edited to turn it into a section view.



Ah, that's better. Now, however, you need to make a few changes to the 3D model. That's no problem; after you've finished, just run FlatShot again and tell it to replace the existing block for each view.

Oops — that is a problem. When you run FlatShot again, it doesn't update the view definition block; it deletes it and replaces it with a new one. All your carefully placed dimensioning, center lines, and hatching have to be redone.

So why did you bother telling us all about FlatShot when it has so many shortcomings?


Two reasons: First, there are a lot of drawings out there that were produced this way, and second, it is still the quickest and easiest way to produce a simple 2D view from a 3D model.

Here's Looking at You, and You, and You


The options for generating 2D working drawings from a 3D model don't end with FlatShot, however. Next in the great cosmic scheme of things is the combination of the SolView (Solid View), SolDraw (Solid Draw), and SolProf (Solitary Professor — oops, I mean Solid Profile) commands. This trio generates collections of 2D objects on various layers in model space, much as FlatShot does, except the results aren't collected into blocks but remain as loose objects.
 


These commands can also create paper-space layouts with the appropriate layers frozen and thawed so that only the correct objects display in each viewport. Let's give this a try — you can follow along using the sample file

  1. If you want to use the ribbon buttons, you have to switch to the 3D Modeling workspace. Select it from the pull-down list at the end of the Quick Access toolbar in the upper-left corner of your screen. If you don't want to switch workspaces, you can always enter the commands directly at the Command prompt instead.
  2. Switch to paper space by selecting the Layout 1 tab, and delete any existing viewport object.
  3. Start the SolView command. What's that — you can't find it on the ribbon? You looked for it in all the logical places, including the Home, View, Manage, and Output tabs? Well obviously you don't think like an Autodesk programmer. The three commands necessary to generate 2D views are (almost) right out in the open, where you would logically expect to find them. Simply navigate to the Modeling panel of the Home tab of the ribbon, click on the Modeling label at the bottom of the panel, and three tiny icons for the three commands will pop up. Click on the first one on the left. Now wasn't that easy?
  4. AutoCAD presents you with four options. Start by entering or selecting UCS.
  5. Enter W for World. This shows you a top view of the part, because that is how this particular model happens to be oriented in the world coordinate system.
  6. AutoCAD asks you for a view scale factor. A factor of 0.5 works for our current model.
  7. When you are prompted for a location for the center point of the view, choose a point in the upper-left corner of the layout. Caution: Don't zoom or pan, because this messes things up! Now (finally!) you are shown a preview image, so you can see if your guess for the scale factor was correct. If it wasn't, you have to Escape and start over. Okay, not really, because the scale and location can be fixed later, but this can get a little messy. It's often easier to start over.
  8. Keep adjusting the view center until the preview pleases you, then press Enter to lock it in.
  9. Select the two corners of a window to define the actual viewport size.
  10. Enter a name for the viewport — “Top” would be logical — and you're… done?
  11. Nope, you're not done if you don't want to be done. AutoCAD reverts to the same prompt as step 4. Let's continue.
  12. Select the Ortho option.
  13. AutoCAD prompts you to "Select side of viewport to project." Select the bottom edge of the viewport you just created.
  14. Now AutoCAD wants a viewport center location, but notice how you can only move in the y direction (even if Ortho or Polar are turned off), and you weren't asked for a scale factor. You asked AutoCAD for an ortho view, so you get an ortho view.
  15. Select the center for the new view, then the corners of the view window, and then name the view Front.
  16. Yet again, you can continue specifying views. Set up an Ortho view from the right side of the Front view and call it Right.
  17. When you get back to the four-option prompt, press Enter to exit the SolView command. You should end up with something like this:


    Three views created by the SolView command.



    Before we move along, it's probably a a good time to lock the viewports so their scales and ortho alignments don't get disturbed. The easy way to do this is to select them, then click on the little padlock icon in the lower-right corner of your screen.

    There are actually two padlock icons in this region of your screen. The right one locks window and toolbar positions, so you want the left one, which locks viewports. Hover your cursor over it for a second until the tooltip pops up to confirm that you have the correct one.

    Hmmm, not very impressive. It's just three views of the original solid.


    Ah, but now comes the magic.
  18. Start the SolDraw command (the middle of the three tiny icons on the Modeling panel pull-down list) and select the three view boundaries. Presto!


    SolDraw turns 3D model views into 2D drawing views.


    But this is just like FlatShot! Hidden lines are continuous, and what are those boxes around each view?

    The boxes are the viewport boundaries, which I'll come back to in a moment.
  19. Now start the Layer command, which brings up the Layer Properties Manager dialog box.


    SolDraw has created ten new layers. 
     
  20. As you can see, SolDraw has created ten new layers. Note the VPORTS layer at the bottom of the list. It has already been flagged as "don't plot," so it won't turn up on any hard-copy printouts. If you find it to be too distracting you can either freeze it, set its transparency to 80, or change its color to a very light grey.
  21. Next, note an amazing coincidence in the list: the first part of each layer name matches the view names we gave them when we used SolView! Go ahead and change the layer colors to suit your standards, and change the hidden layers to have a hidden line type.

    While you're at it, note the three xxx-DIM layers. SolDraw has thoughtfully provided them so you can add dimensions to your views.

To understand how all this works, go back to model space and set the transparency of the 3D_model layer to 90. The figure below reveals the secret: SolDraw is sort of FlatShot at heart. It creates the appropriate layers, flattens the model to 2D objects, and then sets the layer visibility in each viewport so only the appropriate layers display in each viewport. The difference is that it doesn't create blocks of each view.


SolDraw's inner secret revealed!


So far, so good. As compared to FlatShot, the SolView/SolDraw combination seems to take an extra bit of work, but it can generate multiple views in one hit.

But Wait — There's More!

Be sure to come back for the next Learning Curve, which will demonstrate how to create isometric views, cross sections, and auxiliary views; how to apply dimensions; and how to set up a template file to save you a lot of time when creating 2D views from 3D models.

And Now for Something Completely Different

There is a bit of a trick to riding a boogie board on the surf in Maui (or just about anywhere there is surf, for that matter). Most beginners grip the sides of the board near its back edge and hold the board at arm's length in front of them. As a result, they simply sink into the wave and don't get a good ride — if they get a ride at all.

The correct way is to hold the sides of the board near its front edge. When you launch onto a wave, pull the board back so it is totally under your torso and your head hangs a bit over the front edge. You should now be able to ride the wave right up to the beach.

 


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