Mirror entities in sketch in Solidworks - Cell-by-Cell Formula Trace

Sample Data

Coordinates of a line segment and a mirror line in a 2D sketch. The goal is to find the mirrored line coordinates across the mirror line.

Cell	Value
A1	Line1 Start X
B1	Line1 Start Y
A2	2
B2	3
A3	5
B3	7
A4
B4
D1	Mirror Line X1
E1	Mirror Line Y1
D2	4
E2	0
D3	4
E3	10
D4
E4
G1	Mirrored Line Start X
H1	Mirrored Line Start Y
G2
H2
G3	Mirrored Line End X
H3	Mirrored Line End Y
G4
H4

Formula Trace

MirrorPoint(Px, Py, Mx1, My1, Mx2, My2) = Reflection of point (Px, Py) across line through (Mx1, My1) and (Mx2, My2)

Step 1: Calculate mirror line vector: dx = Mx2 - Mx1, dy = My2 - My1

Step 2: Calculate vector from mirror line start to point: px = Px - Mx1, py = Py - My1

Step 3: Calculate projection scalar t = (px*dx + py*dy) / (dx*dx + dy*dy)

Step 4: Calculate projection point on mirror line: proj_x = Mx1 + t*dx, proj_y = My1 + t*dy

Step 5: Calculate mirrored point coordinates: mirrored_x = 2*proj_x - Px, mirrored_y = 2*proj_y - Py

Step 6: Repeat steps 2-5 for line end point (5,7)

Step 7: Final mirrored line coordinates: Start (6,3), End (3,7)

Cell Reference Map

    A     B       D     E       G     H
1 |Line1 Start|Line1 Start|Mirror |Mirror |Mirrored|Mirrored
  | X        | Y        |Line X1|Line Y1|Line X  |Line Y  |
2 | 2        | 3        | 4     | 0     |       |        
3 | 5        | 7        | 4     | 10    |       |        
4 |          |          |       |       |       |        

Cells A2:B3 hold original line start and end points. Cells D2:E3 hold mirror line start and end points. Cells G2:H4 will hold mirrored line coordinates.

Result

    A     B       D     E       G     H
1 |Line1 Start|Line1 Start|Mirror |Mirror |Mirrored|Mirrored
  | X        | Y        |Line X1|Line Y1|Line X  |Line Y  |
2 | 2        | 3        | 4     | 0     | 6     | 3      
3 | 5        | 7        | 4     | 10    | 3     | 7      
4 |          |          |       |       |       |        

Mirrored line coordinates appear in columns G and H. The original line from (2,3) to (5,7) is mirrored across the vertical line x=4 to (6,3) to (3,7).

Sheet Trace Quiz - 3 Questions

What is the vector direction of the mirror line?

A (10, 0)

B (4, 4)

C (0, 10)

D (2, 3)

Key Result

Mirror entities in sketch reflect points across a defined mirror line by projecting points onto the line and reflecting them symmetrically.