Subtracting objects, then making new solid object

[Anonymous]

I am trying to cut an object in half. I extruded a line which marks the half way point. My first try, I selected Trim from the surface tab. I selected the white object on the 0 layer as the object to be trimmed and pressed enter. I selected the red plane which is on my CUT layer to mark where I wanted to trim to. It then asked me to select the area to trim. After selecting either half, I get a message stating that the trimming body does not define a trimming area on the picked surface or region. 

I then exploded the 0 layer item and repeated the process. Now, it looks as if I have the item separated but both halves are still present. They highlight separately though when I select each. I Simply deleted the half i didnt want now and the elements of the circles that make the hole cutouts that I did not want. The side lines need to be shortened to the midway point now but I'm not sure how to. Also, I need to combine what is left over to make it a new solid. I'm not sure how to do this either. 

I am wondering if my thought process for this is correct, of it there's an easier (or better) way to do this. Any help is appreciated. 

I've attached the file I originally started working with.

[Anonymous · Accepted solution]

You cannot TRIM a block in this manner.

1. explode block until it is simply a solid

2. SLICE object in half and delete half you do not need or use a SUBTRACT on another solid to remove other half.

My preferred method would be slice.

Thanks.

[Anonymous]

Thanks, the method of slicing worked. Since I am wanting to cut the object in half, is it possible to carry over the fillet edge to the new squared corners? I'm not sure of the radius and I'm not sure how to check it. I can post a new topic on this if appropriate. Thanks.

[Anonymous]

With a slice there is no way to carry it over that I know. You would need to measure and re-fillet that edge.