Connecting arcs to create 3D model


#1

When I have two 2D arcs to connect them to create 3D object I am using line tool. But this is very slow. If I had more faces it would take much time. So are there some steps to make it faster?

Also when you need to select all edges so reverse faces of the new object, how do you select all faces or how do you select all edges (except faces) to hide them?


#2

It’s more complex if the start profile’s face and the end profile’s face are not equivalent, or they do not have parallel planes.
However, in your case why not PushPull the selected face up to the ‘end-face’ - thereby doing the operation in one step.
Because you have ill-advisedly colored the faces [i.e. it’s best to use View > Monochrome mode!] we cannot determine the extruded face’s orientation.
If extruding it leaves a ‘hole’ they use PushPull+Ctrl to force the face to remain.
If the extruded faces look outwards [back-face color] then select them all, and use context-menu ‘Reverse’…


#3

My thought exactly, why join the arcs when you can just push pull? Unless I’ve mis understood.

On the colour side of things, I have a scene called modelling, which has monochrome face settings. Even if the model is coloured, I switch to this scene to make any changes, so I always draw in black/white.


#4

I do not remember every step I did, so I would ask this question too… For me to create the arcs of a slab was bigger problem. I needed first to draw line, then one arc, then uncurve, then delete a line, then rotate it, then recurve… then I had done the same things with second arc and joined them with a line. One side done. Selected. Copied and move to opposite side. Then I have draw the lines manually. Maybe it was stupid idea to do it like this.

I add images of the results. I see in monochrome one side is not reversed.


#5

Draw an arc.
Offset it the required distance.
Draw lines across the two gaps.
The second line should cause a face to form in the C shape.
Use PushPull on that face to extrude it the required amount.
If the extrusion’s faces look outwards [i.e. you see back-faces in Monochrome mode] then select all and reverse those faces using the context-menu tool.


#6

Well, If I need to select the edges or faces which are reversed, it is not that simple. When I select them and reverse, so the faces from the opposite side of the model are reversed too, because the select tool using drag from left to right selects all faces, not only those visible. Is there some trick to save the work?


#7

Only faces can be reversed.
You can select faces individually [one click], then hold Ctrl to add extra faces to the selection…
Once the desired selection is made use ‘Reverse’.
If ALL connected faces are reversed then you can reverse just one face, Reverse it, the with it still selected use the context-menu ‘Orient’ tool. All connected faces will orient to match - Caveat: non-manifold surfaces can produce unexpected orientations - i.e. if an edge has more than two faces SketchUp has to guess their proper orientations and it usually fails to live up to your hopes and expectations !


#8

Oh, that’s cool! I had no idea I can use the offset tool for duplicating 2D shapes like this and change the shape this way. Thank you.


#9

I believe this is what TIG is saying:

I find it easier to draw the largest arc first then offset to the smallest. I got some unwanted extensions on the arc, note how I add an extra temp line to isolate the unwanted for deleting. This way you don’t have to explode the arc.

Hope this helps


#10

I have no measure to find out the position of the second (lower) block/slab. So I have drawn the top one and then I tried to draw the arc. But in case it is definitely simpler.

I thought about doing it differently, instead offseting it on the red axis, I would use the green one. But then I needed to explode it and move the vertexes to correct the length of the lines from the curves.

Your trick to skip exploding, is also very useful for me.

Thanks


#11

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