"Projection" Projection and View PPT Courseware 6

Description

"Projection" Projection and View PPT Courseware 6

think about it

A round object looks like ( ) under the projection of sunlight

A. Circle B. Oval

C. Line segment D. All of the above are possible

Want to discuss

Observe as shown in the figure. These three figures respectively represent the projections formed by the same triangle ruler under sunlight. Which of the projections in figures (1), (2) and (3) is the central projection and which is the parallel projection? What is the difference between the positional relationship between the projection line and the projection surface in Figures (2) (3)?

Question 1 Place a straight thin wire (recorded as line segment AB) in three different positions:

(1) The wire is parallel to the projection surface;

(2) The wire is inclined to the projection surface;

(3) The wire is perpendicular to the projection surface.

What is the shape of the orthographic projection of the wire in the three situations?

Question 2 Place a square piece of cardboard P (for example, square ABCD) in three different locations

(1) The cardboard is parallel to the projection surface;

(2) The cardboard is tilted to the projection surface;

(3) The cardboard is perpendicular to the projection surface.

What is the shape of the orthographic projection of the cardboard in the three situations?

induction:

When a certain surface of an object is parallel to the projection surface, the orthographic projection of the surface is _________ with the shape and size of the surface.

Explore Draw the orthographic projection on the projection plane P of the cube placed as shown in the figure

(1) One face ABCD of the cube is parallel to the projection plane P;

Solution: The orthographic projection of the cube is square A′B′C′D′, which is congruent with one face of the cube.

(2) One surface ABCD of the cube is inclined to the projection surface P, the upper bottom surface ADEF is perpendicular to the projection surface P, and the diagonal AE of the upper bottom surface is perpendicular to the projection surface P.

Solution: The orthographic projection of the cube is a rectangle F'G'C'D'. The length of this rectangle is equal to the diagonal length of the base of the cube, and the width of the rectangle is equal to the edge length of the cube. The line A'B' connecting the midpoints of the upper and lower sides of the rectangle is the projection of the side edge AB of the cube and the other side edge EH it faces.

summary:

When a certain surface of an object is parallel to the projection surface, the orthographic projection of this surface has exactly the same shape and size as this surface.

Keywords: Projection and view teaching courseware, projection teaching courseware, New People's Education Edition ninth grade mathematics second volume PPT courseware, ninth grade mathematics slide courseware download, projection and view PPT courseware download, projection PPT courseware download, .ppt format

For more information about the "Projection and View" PPT courseware, please click on the "Projection ppt Projection and View ppt" tab.

Projector curtain whiteboard PPT background picture:

This is a projector curtain whiteboard PPT background picture; Keywords: curtain, whiteboard PowerPoint background picture, still life slide background picture, .jpg format;..

"Projection" PPT courseware:

"Projection" PPT courseware Part One: Introduction of new lesson Do you know the relationship between objects and shadows? When objects are illuminated by sunlight or lights, they will form shadows on the ground, walls, etc. It can be seen that shadows are closely related to the shape of objects. Object and its...

"Projection" PPT:

"Projection" PPT Part One Content: Concept The light of candles and light bulbs can be seen as emitting from one point. Like this, the projection formed by the light emitted from a point shining on the object is called central projection. Sun rays and searchlights...

File Info

Update Time: 2024-11-02

This template belongs to Mathematics courseware People's Education Press Ninth Grade Mathematics Volume 2 industry PPT template

Preview