This is an exercise in creating, using and updating Blocks in AutoCAD, as well as using AutoCAD's three-dimensional qualities. It will require working with layers, drawing lines, arcs, and circles, creating a block and inserting it into a drawing, re-defining the block and using the 3D commands. The end result will be a drawing which will be plotted on the HP Laser Jet printer.

1. Start up AutoCAD.
2. Open the previous drawing "<date> Art Gallery with Tables and Chairs.dwg"
3. Save it as "<date> 3D Art Gallery with Tables and Chairs.dwg."
4. "Insert" block "CHAIR" in a scratch area of the drawing. Remember how to do this from the last exercise? If not, go back to those instructions and review the process of "Inserting" a block.
5. "Explode" this block by using the Explode command. This will convert the block from a block to a group of lines and a circle.
6. At this point, it would be helpful to work in an isometric view so you can see the 3D aspects of the chair. To do this, select one of the isometric views on the "View" toolbar, or type VPOINT<RET> 1,-1,1<RET>
7. Change the thickness of all of the pieces of the exploded chair block to 2" by highlighting them and changing the "thickness" property on the Properties Palette to 2".
8. Change the thickness of the back of the chair (all four lines) to 1'-6".
9. Change the elevation of all objects in the chair to 1'-3" by highlighting them and changing the "elevation" property on the Properties Palette to 1'-3".
10. Change the elevation of the circular chair pad to elevation 1'-5".
11. Extrude the circular chair pad 1" using the Extrude command (ext<RET>).
12. Draw a 3D face on the top of the chair back and on the top of the chair seat (under the pad). Select "Draw" from the pull-down menu, then "Surfaces" then "3D Face." Then pick the four corners of each rectangle making up the chair bottom and the top of the chair back. 3DFACEs can be either three or four sided, they cannot be given a thickness, but they hide surfaces behind them. You need them to cap the top of the four lines making up the chair seat and the other four lines making up the chair back. Otherwise, these two elements of the chair will seem "hollow" in a 3D hidden line view. OSNAP to the corners of the back and seat to place the four corners of each 3DFACE. Try to develop a consistent method of snapping to these points by going either in a clockwise or counter-clockwise direction around the corners. You will need to select all four corners, and then type <RET><RET> to complete the 3DFACE command.

Note that you will not need to put a 3Dface on the top of the circular chair pad, because circles come with built-in tops.
13. Draw a 2" x 2" leg in each corner of the chair, with a thickness of 1'-3" and an elevation of 0.
14. Make a block out of this same changed chair and name it "CHAIR1". AutoCAD will prompt you with the following: "Block Chair1 exists. Redefine it? <N>" Answer Y <RET> to that question, to proceed with redefining the block. OSNAP the insertion point of the block to the CENter of the chair pad, but use the so-called "XY filters" to select the Z-coordinate of the insertion point as follows:

 

Command: BLOCK<RET>CHAIR1<RET>

Block "CHAIR1" Exists, redefine it?:Y<RET>

Insertion Point: .XY<RET>

of [at this point OSNAP to the CENter of the seat pad circle]

(need Z) [at this point, type 0<RET> (that is, "zero", not "Oh")]

Note that it is very important that the insertion point of a 3D block be set at the 0 elevation, because it will be inserted on the plan at elevation 0. If you simply snapped the insertion point to the circle without using the XY filters to allow an input of the Z coordinate, the insertion point would be located at the Z coordinate of the circle itself which in this case is 1'-5", and thus the chairs would be set onto the plan so that the base of their chair pads are lying on the plane of the floor, not a desirable effect, to say the least.

15. Insert the block "TABLE" in a scratch area of the drawing.
16. Explode this block.
17. Move the table top up vertically in the Z direction to 24" and change the thickness of the table top to 2".
18. Draw a round base for the table, 1" thick, with an elevation of 0, and a diameter of 20", OSNAPing its center to the CENter of the table top.
19. Draw a pedestal stem for the table with a thickness of 23" with an elevation of 1", and with a diameter of 2", OSNAPing its center to the CENter of the table top.
20. Make a block out of this same changed table and name it "TABLE". AutoCAD will prompt you with the following "Block "Table" exists. Redefine it? <N>" Answer Y <RET> to that question, and proceed with making the block. OSNAP the insertion point of the block to the CENter of the table, again using the XY filters like you did in step 14 to set the Z coordinate of the insertion point at 0.
21. Switch to Paper Space. Change the title of the drawing to "GALLERY SETUP WITH TABLES (3D)."
22. Check that your name, the date, and the exercise number are all correct at the bottom of the drawing. If they are not, use the DDEDIT dialogue box to change the wording of the text.
23. SAVE your drawing prior to plotting [always!].
24. Plot this drawing.