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Projection of a Plane — VektorCAD Tutorial

This exercise shows how to draw the projections of a plane (lamina) using VektorCAD. You will build the XY reference, construct a true‑shape polygon, impose the inclination to HP (θ) and the inclination of an edge to VP (φ), then generate the final top and front views. Use Normal thickness for construction/projection/dimension lines and Thick for the final edges of the plane.

Problem Statement

Draw the projections of a regular pentagonal of side 25 mm, having its surface inclined at 30° to the HP and a side parallel to the HP and inclined at an angle of 60° to the VP.

Given - Plane: regular pentagon, side 25 mm.
- Angle made with HP : θ = 30° to HP.
- Angle made with VP : φ = 60°

Objective - Use VektorCAD commands: xyline, ucs, polygon, line, arc, point (if needed), dimlin, dimalign, text.
- Thickness: Normal for XY, projectors, constructions, and dimensions; Thick for final plane edges.
- Turn Entity Snap ON for precise picks.

Step‑by‑Step

1) Prepare Drafting Settings

  1. Line Thickness → Normal

    1. Select Normal from the thickness options (Thin / Normal / Thick).
    2. Use this setting for XY, projectors, and dimensions.

  2. Entity Snap ON

    1. Turn on snaps. Recommended: Endpoint, Midpoint, Perpendicular for accurate alignment.

2) Draw the XY Reference Line

  1. Draw XY Line ≈ 300 mm long.

3) Construct the True Shape in Top View (Plane Parallel to HP)

  1. Select Thick from the thickness options (Thin / Normal / Thick).
  2. From the Rect/Polygon dropdown, click Polygon.
  3. Enter 5 for number of sides.
  4. At the prompt, choose Edge.
  5. Pick a point below XY Line as the first endpoint of the edge.
  6. Enter @25<-90 to draw a pentagon with 25 mm sides, one edge perpendicular to XY.
  7. Label the vertices a, b, c, d, e using Text.

Pentagon

4) Project the Initial Front View (Edge View on XY)

  1. From each vertex (a–e), draw projectors perpendicular to XY, upwards, using Line (Normal thickness).
  2. Since the lamina is parallel to HP, the initial front view collapses on XY:
    1. Mark a′ and b′ exactly on XY where projectors from a and b meet.
    2. (Optionally mark c′, d′, e′ on XY for reference).

Projection

5) Impose θ = 30° to HP (Tilt in Front View)

Rotate the plane about hinge a′b′ so the surface is inclined at 30° to XY.

  1. From the toolbar, click Line.
  2. Right-click → choose Nearest, and snap on XY near c′ for the start point.
  3. At the command prompt, choose Angle and enter 30.
  4. Pick a point some distance away → finish the line.
  5. Using Cutting Arc, transfer distances from the top view (e.g., a/e–c′ and a/e–b′/d′) to the inclined line.
  6. Mark the new points along the inclined line and label them accordingly.

Inclined Pentagon

6) Draw Horizontal and Vertical Projection Lines

  1. From the Line dropdown, click Ray.
  2. Enter 0 → draw horizontals through a, b, c, d, e.
  3. Run Ray again → enter 90 → draw verticals through a′, b′, c′, d′, e′.
  4. Trim excess rays outside intersections.

HV Projections

7) Obtain the Top View After θ

  1. Mark the intersection points of horizontal and vertical projections → label them a, b, c, d, e.
  2. Connect with Thick lines to form the tilted pentagon (true top view).

Top View

8) Impose φ = 60° to VP (Rotate Top View About AB)

  1. From the toolbar, click Line.
  2. Right-click → choose Nearest → snap on XY.
  3. At the prompt, choose Angle and enter -60.
  4. Pick a point below XY → finish the line.
  5. Using Cutting Arc, transfer distances from the tilted top view to the new line.
  6. Mark points a–e and connect with Thick lines.

Inclined Pentagon

9) Final Front View (After Both Tilts)

  1. From new top view points a–e, draw projectors upward (perpendicular to XY).
  2. From θ-tilted front view points a′–e′, draw horizontals.
  3. Intersections give the final front view positions a′–e′.
  4. Redraw final edges in Thick:
    1. Top view: a–b–c–d–e–a.
    2. Front view: a′–b′–c′–d′–e′–a′.

Final Front View

10) Dimensions and Labels

  1. Switch to Normal for dimension lines.
  2. Add:
    1. dimalign → side length = 25 mm.
    2. dimlin → vertical offsets from XY (20 mm, 25 mm).
    3. Angular dimension → angle of surface with XY (θ, φ).

Dimensions

Result Checklist

  • XY drawn (Normal) and labeled.
  • Entity Snap ON; UCS positioned conveniently.
  • True‑shape pentagon drawn in top view with AB on XY (Normal).
  • Projectors built; initial front view lies on XY.
  • θ = 35° imposed: obtained front view after tilt (A'B'C'₁D'₁E'₁).
  • Back‑projected top view after θ (A B C₁ D₁ E₁).
  • φ = 30° imposed by rotating top view about AB to get A B₂ C₂ D₂ E₂.
  • Final front view A' B' C' D' E' obtained by projection.
  • Final plane edges in Thick; all construction in Normal.
  • Dimensions (side length) and labels added.

Variations (practice)

  • Change polygon to hexagon (side 25 mm) or equilateral triangle (side 40 mm) and repeat.
  • Swap order of inclinations: first set φ then θ.
  • Try a case with the plane perpendicular to VP initially (true shape in front view); adjust the steps accordingly.

Commands Recap

  • xyline — draw XY reference (Normal).
  • Thickness — Normal for construction; Thick for final plane edges.
  • Entity Snap — keep ON for accurate endpoints and intersections.
  • ucs — reposition origin near work area.
  • polygon — true‑shape lamina in top view (edge method, side = 30 mm).
  • line — projectors, references, and edges.
  • arc — swing/rotate views to impose θ/φ using arc intersections.
  • point — mark auxiliary points if needed.
  • dimlin, dimalign — linear/aligned dimensions (side length, offsets).
  • text — labels and angle annotations.

You’ve completed the projection of a plane using auxiliary construction and rotation: clean final views in Thick with all supporting geometry in Normal for clarity.