Unit 1ProjectionsHARD

Dihedral Angle Between Two Planes

Two planes intersect along a line. Plane1 makes 45° with HP and is perpendicular to VP. Plane2 makes 60° with HP and is perpendicular to VP. Find the dihedral angle between them.

6,100 views

Solution Diagram

Solution diagram for Dihedral Angle Between Two Planes
Click to enlarge

Step-by-Step Construction

  1. 1

    Draw traces of both planes

  2. 2

    Both are perpendicular to VP, so VTs are perpendicular to XY

  3. 3

    HT of plane1 makes 45° with XY, HT of plane2 makes 60° with XY

  4. 4

    Lines of intersection of both planes with HP are the HTs

  5. 5

    Angle between HTs = 60° - 45° = 15° (if on same side of XY)

  6. 6

    But dihedral angle is 3D angle between planes

  7. 7

    Draw perpendicular to line of intersection from any point

  8. 8

    True dihedral angle shown in view perpendicular to line of intersection

Pro Tips

  • •Always verify your measurements with a scale before finalizing the drawing
  • •Use construction lines lightly and darken the final solution
  • •Label all important points and reference lines clearly

Quick Actions

Related Questions

Angle Between Two Lines

Unit 1

Rabatment of a Plane

Unit 1

Line Perpendicular to a Given Plane

Unit 1