Hi,

I am trying to make a back cover for an e reader (LINK) using surfaces.

However when I make the surface using either Lofted surface or Boundary surface I end up with a weird shapes in the corners of the backplate.

How can I get rid of these?

Creating another guide sketch 2/3 up from the ground surface doesnt work either.

Any ideas on how to make this smooth?

Thanks,

Joeri,

Just in case you cannot open a 2014 document, here is a step by step.

Start with 2 curves on planes separated by whatever distance you need. Because the back is not reall flat in my concept, I made it 2mm less than the overall thickness. Notice the Conic Arc used in the second sketch.

Next I added the curves that defined the convexity of the back surface, because I need to make the curves that define the edges next and they need to be at least tangent to that convex surface.

Next I added the curves that define the edges.

Now extrude those side edges. It is always best to use the simplest feature you can to create any surface. Since the edges are constant until the corners, an extrusion is as simple as you can. I also added some planes through points on the first 2 sketches to define the stopping points for these extruded surfaces.

Here is the corner blend, notice the edge constraints: tangent to the extruded sides and normal to sketch 1. Also notice the tangent influence is turned up to 100% at the sides.

And finally finish off the form with some mirrors (with knit option selected) and a Fill Surface (with curvature along the boundary and those convexity sketches used for constraint curves).