Creating a face with arcs and lines

Normally I use the add_face method to create a face and looking at the documentation I should be able to use the same method where I have a number of points along with a couple arcs that will define the geometry of the face. The funny thing is I have never run into this before, I’ve only had to deal with polygon faces (only straight segments) or circles.

Does anyone have an example of creating a face with the add_face method that involves straight segments (ie. points) and arc(s)?

In order to include an arc into the add_face() signature you need to convert the arc into it’s constituent point array. Here is code that creates an arc, a point, then calls add_face() with the point appended to the arc point array.


I am more inclined to use #find_faces

so adding to the API #add_arc example

centerpoint =
# Create a circle perpendicular to the normal or Z axis
vector = 0,0,1
vector2 = 1,0,0
vector3 = vector.normalize!
model = Sketchup.active_model
entities = model.active_entities
edges = entities.add_arc centerpoint, vector2, vector3, 10, 15.degrees, 135.degrees
arccurve = edges.first.curve
# add an edge to close the arc.
closer = entities.add_line(arccurve.first_edge.start, arccurve.last_edge.end)
# let the edge find it's own face.


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Thank-you for both or your examples I learn something new every day when it comes to the Sketchup API.

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One potential subtle difference between the two approaches: in @john_drivenupthewall 's technique, #find_faces will find all faces bordered by the closer line, not just the one bounded by the new geometry you just created. I’m not sure whether #add_face in @JimG’s method will also find adjacent faces or only the one you added (not where I can check right now). But in either case, you might consider enclosing the geometry in a group if you don’t want to affect anything else.

find_faces draws every possible face that ca be drawn, similar to what SketchUp does when you draw edges through the UI. When creating a drawing tool that draws edges this is useful to match the native behavior but when making a plugin that draws more high level stuff you typically want to specify yourself exactly what faces to draw.

I’d typically use add_face with the series of edges or the points as arguments.

add_face also accepts edges. You can create edges up front and then create the face.

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