Topics for Midterm Lecture 11 Instructor: The students are to continue working on descriptive or space geometry. Notes are provided in this lecture as a review for the midterm exam. Autumn Quarter

Topics For Today Drawing No. 20 is due Today’s Drawing: Space geometry Midterm Tuesday Instructor: Ask if the students have any questions about space geometry or about the midterm exam. Autumn Quarter

Topics for Midterm on Tuesday Orthographic projection drawings, i.e., 3-view drawings Isometric projection drawings Missing line(s) Missing view Graphing Space or descriptive geometry Instructor: Anything is fair game that the students have turned in and had graded and returned. Autumn Quarter

Topics for Midterm on Tuesday Four problems: 75% to be done by hand-sketching 25% to be done by AutoCAD You will not be allowed to use any files from your disk for the CAD work Instructor: Advise the students to do the CAD problem first so that there is not a mad dash to get printing done at the end of the hour. Also remind them that the CAD drawings have to be identified by name, seat number, section, and instructor. Autumn Quarter

Today’s Assignment Dwg 21 & 22 – SG-6A Shortest connector between two lines, through a disk. Worth two drawings Due at beginning of next lecture Instructor: The space or descriptive geometry problem has to do with the shortest line. The instructions are provided as part of the students’ packets. This problem is to find the shortest distance between two non-intersecting lines in space. The solution is to make a copy of one line and the copy go through the end of the other line. Once you have the second line and the copy intersecting it, you have a plane. CAD programs can give you the view of the plane true size. Once you have the true size of the plane, you can draw a line (choose a new color) from the apparent intersection of the original two lines but attach it to the first line. Then go to the apparent intersection again and have the line you are drawing attached to the second line. Once you have the shortest line, you can put a point symbol at the midpoint of the connector. With the point symbol in place, you can go back to the view of the true size of the plane and draw a circle of the proper diameter with the center at the midpoint and perpendicular to the shortest connector. Using different colors for each line and the point symbol helps keep the construction correct. Autumn Quarter