COMPUTER AIDED ARCHITECTURAL DESIGN

Workshop 3 Notes, Week of September 16, 2013

Accudraw and Simple Solids

1. ACCUDRAW

The accudraw coordinate dialog box is anchored in the lower part of the application window and echos back coordinate information:

Dragging the dialog box out of the margins of the applicaiton window will change its shape as follows. This may be more convenient for juxtaposition with the drawing elements in some situations.

Accudraw is on when you see a dialog box where you can enter distances (XY&Z) of elements that you are drawing. Your curser will also have a box around it with square crosshairs. This works with many tools (drawing lines, copying, scaling, etc.).

(If Accudraw is not on, click on the green and red crosshairs symbol in your toolbox Attribute toolbox at the top of the screen.)

To ensure that you are drawing at right angles, allow your line to lock into the appropriate direction. (When your line become thick). Press enter to lock into this direction. When drawing at an angle, Accudraw will adjust to this angular field. To return to the xyz orientation, press Shift and “T”.

READ ACCUDRAW HANDOUT FOR MORE DETAIL ON BASIC CONCEPTS AND TOOLS

TECHNIQUES COVERED

• XY(Z) axes
• Dynamic Coordinate Readout / Entry
• Precision input MU:SU -Masterunit: Subunit OR Decimal, eg., 5:6 (five feet, six inches), or 5.5
• AccuDraw Settings: note display of coordinates echoed back inside coordinate dialog box.        
• Left mouse button click inside of coordinate dialog box – give AccuDraw input focus
• Context sensitivity to mouse direction
• If you are moving the mouse along the x or y axis, just type in distance to constrain dimension
• Last distance, PGup recalls last distance from cache memory
• Popup calculator is activated from the X, Y, or Z coordinate text box by entering an "=" key
• Coordinate input window can accept variables (pi) and parenthetical expressions, e.g., "3 + 4", "3 + (2 * 4)"
• Spacebar change mode – polar / rectangular coordinate systems
• Composite distances (enter value along X axis, then along Y axis for single data point) and trackings
• Compass Quick Key Options:
• Shift T -Return to Top
• RQ – rotate quick
• RE – rotate to element
• Quick Locks – alignments (Mayline/triangle paradigm)
• Enter key in any coordinate text box – Axis lock
• Enter  X, Y, or Z and constrains the dimension in corresponding axis
• Measured distances (and calculations) may be enter withing algebraic expressions, e.g., 
• Tenative snap - concurrently press  first and third mouse button when entering a data point 
• Tenative snap and letter "0" - used to offset location of mouse from tentative snap
• Shift Origin > Letter "O" - offsets location of mouse

2. ACS PLANE LOCK AND ACS SNAP LOCK

a.Open the active locks menu, located in the bottom right corner next to the snap menu.

b.The ACS plane Lock forces the drawing plane to the ground plane.
c.The ACS plane snap Lock forces object snaps to attach at the ground plane (this lock should be turned off for today's exercise).
 

There are a range of solid modeling options: shapes, extrusions. This includes both standard solids in the menu "Solids Modeling" we will explore today, and as we will see later on,  so-called feature or smart solids that allow for parametric control.
 

3. USING ACCUDRAW IN 3D

    * Accudraw allows you to draw in Perspective View, providing you with 3 default drawing planes.
    * Pressing "T" gives you Top drawing plane in x and y, pressing "S" gives you Side drawing plane in y and z, pressing "F" gives you Front drawing plane in x and y.
    * Locking on x, y and z dimensions are possible in all three drawing planes.

4. ROTATING ACS PLANE IN 3D

    * While Accudraw is on, press "R" then "A" to activate 'Rotate ACS.'
    * You can pick 3 points to set a different ACS plane in Perspective View.
    * This allows you to draw on that plane, making it easier to draw on the elements that may be rotated or slanted such as a roof.
    * Pressing "T", "S" and "F" still gives you default 3 drawing planes when ACS plane is rotated.

5. SOLID PRIMITIVES

   * To bring up the solid tools go to: Task Manager > Solids Modeling > 3D primitives.

Note: These tools can be activated by specifying their letter and number address. The solid slab tool above can be activated by the letter and number "E1". The torus (doughnut shape) can be actived by the letter and number "E8".

    * These tools allow you to construct Slab, Sphere, Cylinder, Cone, Torus, and Wedge by drawing a series of vectors to describe that solid. The sequence of vectors parallels a step by step sequence for geometry developed by Keith Critchlow (see his book  "Order in Space").
    * The Slab, Cylinder, Cone, and Wedge all work in a similar fashion.
    * When drawing a Sphere however, the very center of the Sphere is placed along the ground plane. To move the Sphere up, get into front view and use the move tool to move the Sphere up to the ground plane by first selecting the Sphere, then typing " F" to move Accudraw to the front orientation, and then finally move the Sphere. To get Accudraw back onto the ground plane type " T" for top.
    * For the Torus tool, it is easier to create one if you type in an explicit value for the primary radius, secondary radius, and/or angle in the place torus dialog box.

7. SOLID PRIMITIVES

 Boolean constructions based on solids consist primary of the Union, Intersect, and Difference(Subtract) operations. Create 3 pairs of solid spheres in the ground plane as follows.

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8. CONSTRUCTION OF A PENDENTIVE *

 Intersect a cube with the upper half of a sphere.

Subtract three cylinders, one oriented for each center x, y and z axis of the previous solid.

Size and juxtapose a solid sphere to fit the upper hole along the z axis created by the previous step.

Copy and reduce in scale the previous solid sphere keeping the same center point.

Subtract the inner sphere from the outer sphere.

Create a solid cube of sufficient size to subtract the lower half of the hollow sphere created in the previous step

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* This exercise was developed as a tutorial by Professor William Mitchell, MIT. ....

9. CONSTRUCTION OF SOLIDS USING BOOLEAN OPERATORS WITH GENERATIVE COMPONENTS

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10. CONSTRUCTION OF A PENDENTIVE USING BOOLEAN OPERATOR WITH GENERATIVE COMPONENTS

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