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FreeCAD: How to project a shape onto a curve surface?

Update: July 14, 2021
FreeCAD 0.19

In this section, we explain how to project a surface or edge onto a curved surface to create a new shape. This function allows you to create a shape by projecting text, images, etc. onto a curved surface.

Fig. The result of projecting a string shape onto a cylindrical surface
The result of projecting a string shape onto a cylindrical surface

Steps

  1. At first, we should prepare the shape to be projected and the curved surface shape to be projected. In this example, we use a string shape created by Shape StringDraft_ShapeString as the projected shape (refer to "How to create character string shape solids?").

    Fig. Shape to be projected and projection surface
    Shape to be projected and projection surface
  2. Run Projection on SurfaceProjectionOnSurface to show a dialog for projection.

    Fig. Dialog for projection
    Dialog for projection
  3. Push Select projection surface button and select projection surface in 3D view. When we select the projection surface, the shpe including the surface will be displayed translucently.

    Fig. Projection surface setting
    Projection surface setting
  4. Then we set projection direction. If we push Get current camera direction button, the current camera direction in the 3D view will be set as the projection direction. Or if we push X, Y or Z button, each X, Y, or Z direction will be set as the projection direction.

    Fig. Projection direction setting
    Projection direction setting
  5. Then we set shapes to be projected. Push Add face button and select faces to be projected. If you want to deselect a face in the projected shape, select the face again in 3D view. When you select all faces, press the Add face button again to exit the setting.

    Fig. Adding faces
    Adding faces

    If you use Add wire button or Add edge button, you can set edges as shape to be projected.

    Fig. Adding edges
    Adding edges
  6. Select the projection method from "Show all", "Show faces", and "Show Edges". The result of each projection is shown below.

    Fig. Projection as solids
    "Show all": Projection as solids
    Fig. Projection as faces
    "Show faces": Projection as faces
    Fig. Projection as edges
    "Show Edges": Projection as edges
  7. Finally, set the extrusion parameters. The parameters are as followings.

    Extrusion parameters
    Parametersdescription
    Extrude heighExtrude length in projection. This parameter will be ignored in projection as wire or edges.
    Solid depthThe amount of translation of the projected result shape from the projection surface.
    Fig. Configuring extrusion parameters
    Configuring extrusion parameters
  8. After the parameter settings, click OK to create projection result shape. If you want to change color of the result shape, select the shape in model tree and change "Line Color", "Point Color" and "Shape Color" properties at View tab.

    Fig. Changing the colors at View tab
    Changing the colors at View tab
    Fig. Result of changing the colors
    Result of changing the colors

    The projection result shape will be a different solid from the shape of the projection surface. Do boolean operations such as fuse(Fuse operation) or cut(Cut opperation) as necessary.

References