Engineering Graphics ''Planes''

Projection of planes

Introduction Rectangle Circle Rhombus

problem 1: Rectangle 30mm and 50mm sides is resting on HP on one small side Construction

Step 1. Draw a rectangle abcd of sides 30mm & 50mm, which is parallel to HP. This is the top view of the rectangle. Now, draw the projection of it's sides above the XY axis. This is the front view of the rectangle i.e. a'b'c'd'.

Step 2. Now, the front view a'b'c'd' of the rectangle makes 45^o inclination to the HP. Draw it's projection below XY axis, which gives the top view a₁b₁c₁d₁.

Step 3. Now, make 30^o inclination of one of the small side of rectangle a₁b₁c₁d₁. to the VP. Finally draw the points a₁'b₁'c₁'d₁' as shown above .

problem 2 : A circle of 50 mm diameter is resting on Hp on end A of it’s diameter AC which is 30^o inclined to Hp while it’s Tv is 45^o inclined to Vp. Draw it’s projections.

Construction

Step 1.. Firstly, draw a circle of 25 mm radius(or 50 mm diameter) parallel to HP.
This is the top view of the circle. Name it abcd as shown in figure & draw it's projection above the XY axis, which is the front view of the circle i.e. a'b'd'c'.

Step 2.. Now, the front view a'b'd'c' of the circle makes 30^o inclination to the
HP. Draw it's projection below XY axis, which gives the top view a₁b₁c₁d₁.

Step 3. Now, make 45^o inclination of the diagonal a₁c₁ to the VP. Finally draw the points a₁'b₁'c₁'d₁' as shown above


Construction

Step 1. . Draw a rhombus abcd of diagonals 40 mm and 70 mm long respectively parallel to HP. This is the top view of the rhombus. Now, draw the projection of it's sides above the XY axis, which shows it's front view i.e. a'b'd'c'.

Step 2. . Now, the front view a'b'd'c'of the rhombus makes 45^o inclination to the
HP.Draw it's projection below XY axis, which gives the top view a₁b₁c₁d₁.

Step 3. . Now, make 35^o inclination of the longer diagonal a₁c₁ to the VP. Finally draw the points a₁'b₁'c₁'d₁' as shown above