What are Sketches?
A sketch is a rough diagram mainly used to represent objects on a paper or screen. Sketches can be freehand drawings or rough drawings made with the help of basic geometric instruments. We often use sketches to create finished drawings. Designers and artists also use sketches to create a preliminary visual representation of the final object.
What are Oblique sketches?
An oblique sketch is a special type of sketch that is used to represent three-dimensional shapes on two-dimensional planes. We can use oblique sketches to represent different perspectives of three-dimensional shapes like prisms, cylinders and pyramids. Observe the oblique sketch of a cube:
In oblique sketches, the frontal faces and the opposite face of three-dimensional objects are drawn with the true dimensions. The edges of the other faces of the three-dimensional shapes are drawn at a reduced scale. All dimensions of the sketch appear to be equal, even though they are not equal on paper. This helps us perceive the true shape of a three-dimensional object despite the fact that we are not able to see all faces of the shape. Usually, the angle between the edges of the front face and the edges of the side faces is 45 degrees.
How to draw an oblique sketch of a three-dimensional shape?
We can make oblique sketches of three-dimensional shapes with the help of grid paper or dotted grid paper. Follow these simple steps to make an oblique sketch of a cube:
Step 1: Draw the front face of the cube on the grid.
Step 2: Leave one square on all corners and draw the face opposite to the front face. The opposite face should have the same dimensions as the front face.
Step 3: Join the corresponding corners as shown below.
Step 4: Redraw the hidden edges with dotted lines.
Oblique sketch vs isometric sketch
Isometric sketches, like oblique sketches, are sketches that help us represent three-dimensional objects on a three-dimensional plane. But there are some major differences between the properties of these sketches that make them look very different.
Oblique sketches | Isometric sketches |
|---|---|
Oblique sketches are drawn at 45 degrees. | Isometric sketches are drawn at 30 degrees. |
An oblique sketch focuses on the front and rear faces of an object. | An isometric sketch focuses on the edges of an object. |
Solved Examples
Example 1: Draw the oblique sketch of a cuboid.
Solution:
A cuboid is a three-dimensional shape that has six rectangular faces. Follow these steps to make the oblique sketch of a cuboid.
Step 1: Draw the front face of the cube on the grid.
Step 2: Leave one square on all corners and draw the face opposite to the front face. The opposite face should have the same dimensions as the front face.
Step 3: Join the corresponding corners as shown below.
Step 4: Redraw the hidden edges with dotted lines.
An oblique sketch is a type of sketch that is used to represent different perspectives of three-dimensional shapes on two-dimensional planes.
We use oblique sketches to make two-dimensional drawings of three-dimensional shapes. Oblique sketches help us understand the shape of three-dimensional sketches, even though they are two-dimensional drawings of three-dimensional shapes.
Oblique sketches only show us the accurate measurement of the front face of a three-dimensional shape. The rest of the sides are shorter than the true dimensions. This helps us perceive the actual shape of the three-dimensional object. On the other hand, isometric sketches give us the true dimensions of all edges, but it gives us a distorted version of the actual shape of the object.