Grid Modeler has many in-depth functions and advanced usage, please refer to documentation ( https://www.kushirocg.com/gridmodeler )

Usage guide

This is a simple usage guideline of Grid Modeler.

How to use Grid Modeler

1. Select a face, or multiple faces (co-planar), run the tool by right click menu. (you may add it to Q menu for quick access).

2. You will see the grid lines. Your mouse cursor will auto snap to grid lines.

3. Ctrl + mouse wheel to adjust the grid size. 

- You may choose between two size modes (A key), relative mode and absolute mode :

Relative mode :

 Measure your mesh edge length to set the size. 

Absolute mode :

 Use Blender's system measurement. If you want to keep your objects same size, you may use absolute mode.

- You can use Alt + mouse wheel scroll to enlarge the grid plane. The grid plane can be larger than the face. When you want to add new mesh on top of selected face, you always want to Alt-scroll to enlarge the plane before drawing.

4. You can change the grid alignment. Ctrl + Left click an edge, it will align whole grid plane to the edge.

By default, the tool measure the face and orient the plane using longest edge of your face. You can override this by above method.

5. Now you can draw on the grids. During drawing, you can change the grid scale anytime (Ctrl + Scroll wheel), and you can change the alignment too.

6. On the left bottom of the screen, there are some hints for your convenience. 

7. If you want to Copy / Paste / Delete your shape, you may enter "Selection mode". You can switch to selection mode by Right Click mouse button once / Press W key. (right click/W key again to back to normal mode)

In Selection mode, you can drag and draw a yellow rectangle to select shapes. You can select multiple shapes.

You can delete them by pressing Delete key. 

You can duplicate the shape by select it, then press D key.

Also you can press Ctrl + C to copy, and then Ctrl V to paste, Ctrl X to cut. You can paste it many times. 

When you have selected shapes, you can press G key to move it, R key to rotate it, and press M or N key to flip it.

You can press B key to bevel the shape. Select shapes and press B, then move your mouse cursor to adjust. Scrolling the mouse wheel to increase bevel cut.

8. After all, you can Right Click again to leave selection mode, and go back to normal mode. You can continue and draw again.

9. When you finish, you can commit operation by pressing 1, 2, 3, 4 or 5 key on the top of keyboard. 

They represent different operations : 

1 : Cut the face and fill by n-gon

2 : Cut the face and fill by triangles

3 : Create a new face from shape

4 : Boolean subtract cut

5 : Boolean slice

You can still change the operation after commit. (by the blender's menu, left bottom of the screen)

10. When you draw, you can use Circle tool to draw Circle / Triangle / Square / Pentagon / Hexagon, or any edge-shape.

Press C key to activate, press C again to deactivate.

Shift + Mouse Wheel to change the number of circle edges. (turn to 3 edges will become a triangle)

Grid Modeler has many useful functions. You can visit my website for full reference.