Can't convert closed surface to 3d solid

[davidkoh007]

Hi,

I can't seem to be able to convert attached closed surface to 3d solid via CONVTOSOLID.

AutoCAD 2015 just says "Object can't be converted."

I can't find any holes in the closed surface.

I have tried commands like THICKEN, SCULPT without any results.

The objective is to calculate volume of the closed solid object.

Any help will be greatly appreciated.

[parkr4st · Accepted solution]

Take a look at the attached file

I exploded the surface & made  regions.  I changed the color of 3 regions in the corner and deleted one.  See the gap on the lower surface?  That one error stops the CONVTOSOLID.  Probably more errors available.

back to the drafting board and correct the surface.

Many of the regions appear to overlap also. 

[davidkoh007]

Thank you now it works. It seems it was the only error.
You obviously have better eyes, I was rotating the model a hundred times and couldnt see it so I thought there must be some other thing i'm missing. Thanks again.