Chapter 15

Visualising Solid Shapes

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

Introduction

Visualizing solid shapes is an NCERT chapter that makes you familiar with the basics of shapes and geometrical applications of these shapes. You might have come across the solid shapes often around you. We can classify shapes based on the number of axes used to define their dimensions. If you have any object defined using length and breadth only, then it is the two-dimensional shape. If you need three parameters to define the solid shape, then it is a three-dimensional shape. We can use oblique sketches or isometric shapes to depict any three-dimensional shape on 2D paper. Let’s check some examples of geometric shapes of both these categories.

Incorporating any 3D image on a 2D flat surface will remove any one of the solid shape axes. That part of the geometric shape will be depicted on the isometric view on the 2D plane. Visualizing solid objects by drawing solids on a flat surface is a great manual method to print any 3D design in a 2D model. Architects and engineers use this process to build the prototype of their device on paper. There can be two methods to draw solids on a flat surface. They are discussed below.

Oblique sketches are a rough diagram of any 3D object drawn on a flat surface to give a brief idea of that object. It doesn’t show the real dimensions of the 3D object and hence is not used in real measurement patterns. For example, if you draw a cube with freehand drawing, it will be an oblique sketch.

Isometric sketches are also used to depict any 3D shape on a flat 2D surface. These shapes are in correspondence with the measurements of the actual faces of the solid. The isometric sheet consists of equilateral triangle patterned dots that are fashioned on the plane sheet forming two different layers of dots.

We can check solids from different viewing angles and know about their properties. Some of the ways to check the solids in different ways are.

  • Viewing the cross-section
  • Using shadows
  • Viewing at different angles

In isometric projections, you can view solids from different angles: front view, side view, and bottom view.

Another way of viewing any solid object is to cut it into slices to get a cross-section. For example, if you are given a cube, and cut it from between, you’ll get a square shaped cross-section.

We can visualize different sections of solids using shadows. When you project a light source like a torch on the given solid object, you’ll get a shadow projected on the other side of the light source. Different solids have different shadow shapes. For example, the circle will have an oval shadow; the triangular object will have a cone-shaped shadow and more. Any 3D object will have a 2D shaped shadow projection.

Visualizing solid shapes is an important chapter in the NCERT textbook covering the basic difference between the 3D and 2D objects around us. The basic difference between these two objects is the number of the axis used to represent them. In three dimensional figures, we use three-dimensional axes to represent the object’s length, breadth, and height. 2D shapes can be easily made on a flat surface as we only need two-length elements for them. But depicting 3D objects is a challenging task as you only have two axes on a flat surface.

  1. What do solid shapes look like?
  2. We can have 2D and 3D shapes that are solid. Solid shapes can be of different types, and we see them around us every day. Such as squares, spheres, circles, rectangles, and more. We can depict any solid object on a flat surface in different types. Those are discussed above.
  3. How do you visualize solids?
  4. We can visualize solids by considering some key points like the number of faces, vertices, and edges if we are told that name a 2D shape that has 5 edges and 4 vertices with all faces being equal in size. Then we can use this information to build a geometric shape that will be similar to a square shape.
  5. How many solid shapes are there?
  6. We cannot define a fixed number of solid shapes because we can always add a face to the predefined shape, making it bigger. Some of the common examples are triangle, square, rectangle, sphere, and more.
  7. What are solid shapes with examples?
  8. Some of the solid shapes with examples are square, cube, cuboid, prism, pyramid, and more. You can also have more shapes like a diamond shape, kite, decagons, and more.
  9. How do you identify shapes?
  10. The basic way to identify any shape is to draw it by using all the available information. You can be given different requirements like several faces, vertices, edges, and more.

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