"Projection" PPT

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"Projection" PPT

Part One: Concepts

The light from 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.

The sun's rays and the searchlight's rays can be considered to be parallel. Like this, the projection formed by parallel light rays shining on an object is called parallel projection.

Let’s talk

1. When the placement of the projection surface and the object remains unchanged, what is the relationship between the distance of the light source from the object and the size of the projection of the object?

2. When the positions of the projection surface and the light source remain unchanged, what is the relationship between the placement of the object and its projected shape?

Projection PPT, part 2: explore together

As shown in the figure, the orthographic projection of the front surface (R surface) of the cube on the V surface

1. What is the orthographic projection of plane R? What is the orthographic projection of the surface opposite to the R surface?

2. What is the orthographic projection of plane Q? What is the orthographic projection of the surface opposite to surface Q?

3. What are the orthographic projections of edges AB and AE of the cube? What are the orthographic projections of vertices A and E of the cube?

Let’s talk

1. Is the orthographic projection of an object a three-dimensional figure or a planar figure?

2. What shapes might be the orthographic projections of points, line segments, and polygons?

point: point;

Line segment: point, line segment

Polygon: polygon, line segment

Projection PPT, Part 3: Practice

As shown in the picture, Xiao Ming is standing under a street lamp, using the street lamp as a point light source.

Please draw the center projection of Xiao Ming.

The picture below is the projection of a big tree in the sun. Please draw the projection of another tree (represented by a line segment).

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

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"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...

"Parallel Projection" PPT courseware 2:

"Parallel Projection" PPT courseware 2 In parallel projection, when the projection line is perpendicular to the projection plane, the projection of the geometry in the projection plane is called orthographic projection. Explore new knowledge. Place a line segment AB in three different positions: (1) The line segment is parallel to the projection surface. (2) The line segment is inclined..

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Update Time: 2024-10-02

This template belongs to Mathematics courseware Hebei Education Edition Ninth Grade Mathematics Volume 2 industry PPT template

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