Hi guys,

I need help on the model i'm working right now.the model have thickness of 10mm. As shown in the pics, the square sketch which i have split it on the surface solid body is the area that I intend to make as a door.

Question 1:
So right now I cant split the solid body into 2 and hence cant proceed with lip and grove features. Is there any way to to get the split area as another one solid body rather than extrude cut the whole model to get desired area and save as another file name.

Question 2:
Is there any way to discard the lines on the door (red circle). Just desire a blank door without line on it. is there any way to hide line (red circled) when presented together with the full model.

Note:
My early intention when designing this model only want to have a smooth surface along the surfacing area with the reference of top and right plane sketch, however it didn't work out. so I have to draw few spline as reference. That how the 2 intersecting lines got into the box.

attached is the solidworks files for reference.