hollow sphere

 From:  Michael Gibson
4795.10 In reply to 4795.7 
Hi Linda,

> Here some pictures of the kind of spheres I have in mind:

So probably the most general purpose way that will let you try different variations easily is to use the Flow method. Those previous links should help to give you some idea of how to set it up.

But one thing you may run into is that a sphere is a surface that collapses down to a point at its top and bottom pole areas - when you use Flow on a sphere the objects that you are flowing from the base plane onto the sphere will also shrink down at the pole areas as well. if you want to have a more uniform type shape you may want to use Flow to create curves rather than deforming already built solids, and then when you have the curves into position on the sphere you can draw a circle off to the side and use the Sweep command to build tubes around all the paths.

Here is an example - you start with your curves all laid out flat like on a map of the world, and draw a base plane beneath them using Draw solid > Plane, so it looks something like this:



You probably want to have the plane have a 2 to 1 ratio of width to height so that it will generally match the sphere's layout which is a 360 degree revolve of a 180 degree arc. So when you create the plane type in some values for width and height that will give you a 2 to 1 ratio like width of 40 and height of 20.

Now select just those curves and not the plane, so it should look like this:



You can now use the new v3 Flow tool (under Transform > Deform > Flow, it doesn't have an icon yet but the button is there) to map those curves from the plane onto a curved surface. If you do it on a sphere it will be basically the same thing as how a flat map of the world wraps onto a globe.

When you run Flow the first prompt (the prompt shown in the upper-right area of the window which is where MoI tells you want kind of action it is waiting for you to complete right then) is for picking the base surface which is the plane.

The spot where you pick on the plane is significant - it will match things up according to which edges you clicked nearest to. So when you pick the base plane, pick it near this spot here:



Then for the next stage where you're picking the target surface click the sphere near its vertical seam edge here:




That will then put the curves onto the sphere like this:



You can now delete the sphere and leave just those curves behind:



Now draw a circle somewhere off to the side far enough away so that is outside of the bounding box of the curves, that will active auto-place mode (see the Pod video tutorial for some more explanation of auto-place mode http://moi3d.com/2.0/docs/tutorials.htm) :



Then you can select that circle and use Construct > Sweep to sweep it along all those curves to make tubes:



MoI can have difficulty trying to boolean together tubes that criss cross each other in that manner though, so if possible you probably want to just leave them how they are instead of attempting to boolean all those together, that's a difficult case for the booleans to handle very well. But for a lot of things you can probably just leave them like that.

Hope this helps!

- Michael