How to animate morphing a rectangular plane into a sphere

Question

How to make a grid-to-sphere animation like this?

Answer 1

I think the one who made that reference GIF (in another software) used two Simple Deform modifiers:

1. Create a plane, switch to Edit mode, SY2. then use a loop cut to divide it into two squares, then subdivide;
2. Add a Simple Deform modifier, set deform method to Bend, use a new empty object as its origin, select the empty, then RX90. (to bend it along an expected Z axis)
3. Add another Simple Deform modifier, also set deform method to Bend, use a second empty object as the origin, select the empty, then RX90, RZ90.
4. At frame 1, set 0 as the Angle value for both Bend modifiers, insert keyframe for them. Then jump to, say, frame 60, set 180 for the first Angle, 360 for the second Angle (for 360, you may have to type on keyboard), again, intert keyframe for both.
5. If normal direction is incorrect, flip it in Edit Mode.

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UPDATE: In the incoming v2.8, the Simple Deform modifer has a new option that allows choosing Local Axis, so you can use only one Empty in this case, like this:

Answer 2

1. Add an UV Sphere, you can use any segments and rings counts (memorize segments). Then rotate it -90d in Y and translate it +1.0 in Z. Adjust the spheres origin to [0,0,0] with Shift+S > To Center and Object > Transform > Origin To 3D Cursor. Important is to not change the scale and have the sphere with radius of 1.0:

   

2. In edit-mode delete almost all of the vertices but leave the most bottom "meridian". Extrude the mesh in Y direction to a distance of 3.142 with E + Y + 3.142. Subtract 2 from your segment count and divide by 2, add that many loopcuts ((32 - 2) / 2 = 15 for me):

   

3. Create a shapekey. Switch to 3D Cursor Pivot point and scale the mesh down to 0 in local X axis (hold down Ctrl). Animate this shapekey from value 1.0 to 0.0:

   

4. Add a Simple Deform Bend modifier. Add an Empty as Origin to control the direction of bending. Rotate the empty 90d in X, -90d in Z.

   

5. Animate the modifier's angle from 0d to 180d. Duplicate the mesh and scale it -1.0 in Y. Tadaa!

   

6. Edit: Oh and the Bend modifier can be animated to 360d, so you can extrude the mesh in 3rd step both ways and have the whole thing in 1 piece, no need to duplicate and flip..