Part I: CAD and AutoCAD for the Theater

Chapter Eleven: Create a Sample Drawing


    1. The Stage House
      1. setting up
      2. making walls
      3. plaster line, center line
      4. zero,zero
    2. Adding On
      1. hatching
      2. pin rail

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The Stage House:

The fastest way to start is to try it. Start a new drawing. Call it "Zthtr_gp.dwg". This will be our theater groundplan. The 'Z' on the front will help to organize the theater layers below show layers later on.

First set the drawing [Units] to Architectural @ 1/8" Precision with Decimal Degrees @ 0.00 Precision, Clockwise unchecked, and the Drawing Units for DesignCenter Blocks set to Inches. Set [Limits] from -50'0", -10'0" to 50'0", 60'0".

Load some linetypes for the layers. Type [LT] and press Enter to open the Linetype Manager. The Linetype Manager lists probably only lists the default linetypes: ByLayer, ByBlock and Continuous. Press the Load… button, to open the selection box for available linetypes. Select two common linetypes: Center and Dashed. Select as many linetypes as you want by pressing the Control key while picking from the list. Press Enter. The linetypes load into the current drawing and now appear on the selection list. Press OK to return to the command prompt.

Open the Layer Manager [LA]. The default Layer "0" is always present and the "Defpoints" layer, which does not print is normally present. To create new layers, click on New and enter a name. To change the color of a layer select the layer name or, using the Shift or Control keys, several names. Select one of the selected layer's color icons to bring up Select Color window showing all of the color possibilities. If the Details are currently displayed you can also choose a new color from the drop down list box. Pick a new color. Remember, unless you are printing in color, looks are peripheral. If you are using release 14 or earlier, pen settings are controlled by color number. Color organizes layers and can help make important information stand out to the drafter. Repeat the selection process for Linetype, Lineweight, Plot Style.

Ignor the default layers "O" and "Defpoints". Create the following new layers and assign the following colors, linetypes and lineweights:

Layer Name      Color     Linetype      Lineweight
A-Mech-Eqpm Magenta Continuous 0.25 mm A-Mech-Rail Green Continuous 0.35 mm A-Wall Red Continuous 0.50 mm A-Wall-Htch 14 Continuous 0.13 mm G-Anno-Cntl Blue Center 0.13 mm G-Anno-Iden Magenta Continuous 0.13 mm G-Anno-Plsl Blue Dashed 0.13 mm

Make sure that all of the layers are turned On, are not Frozen, are not Locked, and that the Plot icons are not showing the red "no plot" circle. Don't worry about Plot Style until the time for printing is near.

Set the current layer to "A-Wall" by picking it off of the Layer Pulldown on the Object Properties toolbar. The "A-Wall" layer should now be the current layer name showing in the Object Properties toolbar Layer view window. Color, in the Object Properties toolbar Color window, should be set to "ByLayer", the color window on the left of the view box should be red. The Object Properties toolbar Linetype and Lineweight windows should also be set to "ByLayer". The Linetype view window will show a contiuous line and the Lineweight view window should show a heavy black line.

Now we are ready to make a simple theater groundplan. With width set to 0'0", draw a polyline from point [-20',0] to [-25',0'] to [-25',50'] to [30',50'] to [30',0'] to [20',0'] and press Enter to finish.

If you cannot see the whole line, [Zoom] to [All] and press Enter. AutoCAD zooms out to display the entire drawing limits. Your results should look like my drawing window on the right. This polyline represents the inside of the wall of our stage house.

We will use the Offset command to create the outside wall. When the [Offset] command prompt asks for the "Offset distance or [Through] <Through>:", type in a thickness for the wall of [12] for 12" and press Enter. Select the polyline that you just created. Pick outside of the box. A second polyline forms 12" away matching the shape of the first polyline.

Now we have to close up this wall outline. To make it easier, we should turn on some OSnaps. With the Shift key depressed, right mouse click anywhere in the drawing window. When the Osnap window appears click "Osnap Settings…" at the bottom to open the Osnap settings menu. Click the check boxes until Endpoint, Midpoint and Center are all selected.

We will close the gap on the left (stage right) side of the proscenium opening with a line. With the [Line] command active, pass the pick box over the end of the polyline at -20'-0", -1'-0". A square yellow box (by default) appears at the snap point, the end of the outer polyline. The shape of the snap box highlight depends on the type of snap point, an Endpoint is square, a Midpoint is a triangle, a Centerpoint is a circle. When you click the line will snap to the highlighted end of the polyline. A line will now stretch out or rubberband behind the crosshairs as you move the cursor. Pick near the end of the polyline at -20'-0", 0'-0" or type [-20',0] and press Enter. Press Enter again to close the command. The new line should connect the two polylines.

Now to finish closing the wall. Lets use the Polyline Edit dialog to close up. Type [Pedit], and press Enter. Pick one of the polylines. At the Pedit prompt, "Open/Join/Width/Edit vertex/-Fit/-Spline/-Decurve/ Ltype gen/Undo/eXit <X>:", type [J] for Join and press Enter. Pick the elements to join, the other Polyline and the short Line segment joining them. They will highlight when picked. Press Enter. The command line will tell you that six line segments have been added, if not you may have chosen the same polyline twice so Join again. The Pedit prompt will return at the end of each action. Type [C] for Close and the polylines should close on the other end. The wall is now one closed polyline object. Press Enter again to close the Polyline Edit dialog.

If the polyline does not close up neatly, something is wrong. This is not uncommon. Each of our polylines is made up of five line segments. When joined and closed, there will be only one polyline with 12 segments. If the Pedit Join command did not say that all six line segments were added (the other polyline and the line), the short line segment may not have connected to the exact ends of the two polylines. If lines or polylines do not meet at the exact same point, they will not be joined. You will have to get the ends together before you try to rejoin the line segments. You may not be able to see the gap between two lines unless you Zoom in very close. Unfortunately,AutoCAD will only join entities that meet exactly on their endpoints.

Change Layers to the "G-Anno-Plsl" layer. Draw a line from the -20'-0",0'-0" point to the 20'-0",0'-0" point. This is the "plaster line" or the back edge of the proscenium. It should be a blue dashed line. The dashes may not be large enough on screen to be seen. Try setting the Linetype Scale [LtScale] to 20.

Start another line from the midpoint object snap of the plaster line, which should be the zero,zero point. Because the theater is not symetrical, we cannot snap to the midpoint of the back wall. Instead we must snap to a point on the back wall that is Perpendicular to the wall from the midpoint of the plaster line. With the line from the midpoint active, Shift + right mouse click and pick Perpendicular off of the Osnap menu. A shortcut method for activating the Perpendicular Osnap is to type [per] and press Enter. Now pass the pick box over the back wall line. A square angle with a box in the corner indicates a perpendicular snap point. Click to accept. This is the stage "center line".

But wait, the center line should be on the "G-Anno-Cntrl" layer. Click on the line to select it. Don't select anything else. From the Layers pull-down box on the Object Properties toolbar, select the "G-Anno-Ctrl" layer. The center line is now on the correct layer. Press Escape to deselect the line.

Change back to the "A-Wall" layer to add an semi-circular apron to the stage. Type [Arc] or [A] and press Enter. Select that Endpoint on the wall line at -25',0, type [0,-96] for the front of the curve, press Enter. The last point is on the outside wall, but not at a Osnap point. You'll have to shut of the Osnap toggle or select None from the Osnap menu. Then type [25',0'] and press Enter twice to close. Since our drawing units are inches, AutoCAD assumes that [-96] is -8'-0". Hopefully, you now have a completed wall outline with a curved stage apron. [Save] your work.

Notice that the zero,zero point (0'-0",0'-0") or the drawing Origin point is the center of the plaster line. Theater staging is usually laid out in the same cartesian coordinate system measured stage left and stage right of the centerline and upstage or downstage of the plaster line. With the theater zero,zero and the drawing Origin point aligned, getting accurate locations for staging is a breeze.

chapter index.

Adding On:

Change Layers to the "A-Wall-Htch" layer. It is time to fill in or HATCH the wall. The [Hatch] command will allow you to select drawing objects and fill them with a pattern. The trick to Hatching is to select perfectly closed outlines. The tiniest opening or an accidental line overshoot can cause the Hatch pattern to squirt out the side and streak across the drawing or simply refuse to Hatch. Because of this it is usually easier to Hatch closed polylines. Even then, an unfortunate juxtaposition of corners may confuse Hatch and send an unwanted line across the page anyway. If all the lines are perfectly closed and you still get an unwanted line extending from a corner, try moving the corner ever so slightly (.01").

Because I want my Hatch patterns to be part of the background of the drawing, I always Hatch in a darker color. Adjust the scale of the Hatch so that it creates a pattern to comfortably fill the Hatched entities without blotting them out. If you really do want a blanket hatch fill, use the "Solid" hatch pattern. The denser the Hatch pattern the more memory it will require. If you have a lot of Hatches, you may want to shut off the Hatch layer until you are ready to plot. By using different scales and rotations, it is possible to get varied looks from the same Hatch pattern.

Start by opening the Hatch window. Select a Hatch pattern. "ANSI31" is a generic hatch that makes a great wall fill. Set the scale to 12.0 so the fill is not too dense. Select the wall polyline object by selecting it with the Select Objects button, or using the Pick Points button pick a point inside the wall cavity. AutoCAD will highlight the outline of the area to be hatched. When the correct outline is highlighted, hit Enter. Preview the results before you accept them. If the pattern is too small or too large or if it is skewed the wrong direction you can alter the pattern and look at it again.

By default, Hatch attaches or Associates the hatching to the outline selected. Selecting the hatch object for the wall also selects the wall. If you stretch the wall, you will stretch the hatch. If you erase the hatch, you will erase the wall. Selecting the hatch selects two different objects in the Object Properties window. To see or change properties for the hatch object, you will have to select the Hatch object in the pull-down menu at the top of the Object Properties window.

You can unattach the hatch by selecting Nonassociate in the Hatchedit window or [No] for the Associate property in the Object Properties window. Now stretching the wall will not stretch the hatch object. Erasing the hatch object will not effect the wall.

Now let's add a pin rail and line set indications. The rail will start in the middle of the down left wall, the stage left side of the proscenium. Change to the "A-Mech-Rail" layer and start the Polyline [PL] command. Notice that Osnap has a difficult time snapping to the Midpoint because of all the Endpoints offered by the hatch pattern. You will have to turn Off or Freeze the "A-Wall-Htch" layer.

Start the polyline at the midpoint of the wall [25',0] draw a line up to 4'-0" from the back wall [25',46'] and attach perpendicular to the side wall [30', 46']. Offset this line 3" away from the wall. By now you may have turned off the Osnap toggle. You may want to be using Snap with medium setting of " or 1" and zoom in. This allows very accurate screen picks without constantly using snaps or typed coordinates.

Move to the downstage end of the pin rail that we just drew. We'll draw a line to indicate the first line set at 12" upstage of the plaster line from [26'6",12] to [30',12]. Change to the "G-Anno-Iden" layer and place a Text object to the left (stage right) of the end of the first line set line. The line set identifier will be in Standard style set to Simplex.shx, Right justified, at 6" height. Place it at [26'2",12"]. It will read "1" for line set #1. Rather than draw all of the line set individually, we'll let AutoCAD automate.

We'll Array the text object and the pin rail line. Type [Array], press Enter, and select the two objects. At the prompt type [R] for a rectangular array. Create [60] rows and [1] column. The distance between rows will be [9] for 9 inch spacing. When you press enter, a single column of 60 line set marks, all labeled "1" appears. Unfortunately you will have to edit each text entry using DDEDIT.

When you are done you will have a very simple theater drawing. It should look like the one below. Save this drawing, "Zthtr_gp.dwg", we'll use it again.

chapter index.

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Copyright © 1999 Wm W Wells. All rights reserved.