Project an Orthographic Sketch onto a Hemisphere

[astroglaser]

Hey All,

I'm working on getting a sketch from an Orthographic projection of the night sky to lay on the surface of a hemisphere. The goal is that once the sketch has been deformed back to the surface of the hemisphere, I can move smaller spheres of various sizes to the star coordinates and then use the lines to create pipes along the surface of the sphere. Doing so would reproduce the night sky for a planetarium show geared at the vision impaired. 

Here is an example of a generalized sky created by "Touch the Sky"

I'd love to get everyone's thoughts on this! It should be pretty darn easy to do, given its just converting a 2D sketch to a 3D sketch which lies along the surface of a sphere.

~ Joe G.

[jhackney1972]

It would be a real help to attach a typical image you would want to project onto the semi-sphere.

[astroglaser]

Hey @jhackney1972 ,

I can do that no worries. Here is the Constellation map pulled from Stellarium for the given location and day of a show. I loaded that into Fusion, callibrated it for a 200mm diameter hemisphere, and then plotted the major stars via points in a sketch. I attached that exported DXF file here as well.

[jhackney1972]

Your DXF was basically blank so I converted the PNG to an SVG and used it.  I had some results but there are two reasons they are not satisfactory.  One, the projection to the sphere surface are closest point so the image is not "wrapping" around the spherical surface.  What I did get is also less than desirable since is simply surface cuts that have to be process, very laboriously, into a raised body.  I have attached the model but basically I would call it a total no-go.  Sorry.

[astroglaser]

Hey @jhackney1972 ,

Thanks for the attempt! When I attempted to get the sphere to be projected up onto the dome, I had thought to do the project along a vector method, which should produce something akin to the following:

That should be a very simple projection mapping for Fusion 360 to handle, so I am surprised that it cannot.

Is it at all possible to put a sketched line onto the face of the sphere? If I could get that, I can use the Pipe tool to add in the connections while manually placing the star markers (smaller spheres) by doing a z-move from the sketch to the point it intersects with the surface of the hemisphere.

~ Joe G.

[astroglaser]

Alright, I may have the solution thanks to examining your file @jhackney1972 .

When doing a "Project / Include" -> "Project to Surface" on the sketch of the constellation, you can select "Along a Vector" instead of "Closest Point". If you then take the Z-Axis as the vector, the lines fall directly onto the surface of the sphere as a 3D sketch. You can then select the lines and create a Pipe along them, which follows the surface of the sphere.

I am going to do some sketch work to separate out the stars from the constellation lines, which should make the projections quicker to get done and then report back.

Thanks!!

~ Joe G.