So really enjoying playing around in Blender and came across Daily3D on Reddit which gives prompts to help with practicing your modeling skills. Today’s prompt is “Envelope”. I
Couldn’t seem to figure out how to dome the top properly. Ended up just beveling the edges which didn’t really turn out how I wanted. At least now I know what I don’t know and I can go looking it up.
If you give it a try please post your results in the discussion. Looking forward to seeing what we all create.
Start over with a plane, rotate X 90, delete face only, select the top edge, subdivide at will, proportional edit to sphere, select one vertice and grab Z 
Alright going to give that a try to see what I come up with. Will post the result later tonight
Welp… this was harder to make than it looks… The first part is ok… filling the holes and continue the modeling not so much. Specially when you use Subsurf! 
My envelopes look good looking from the front, but the back of them not so much. but it doesn’t show from the angle of the render so guess it’s ok 
When you start looking at reference images of what it looks like in real life it’s quite a challenge and it’s hard to stop trying xD
But with a strong will, I stopped like this:
Yeah this came out really good…thanks for posting.
