Autocad Coverting to 3D modeling



I would like you to convert the two pyramids into 3d structure.

in this AutoCAD file,

I have two pyramids.

1- the one has a circle at a specific distance 20 mm. I want you to convert that into 3d solid. Then, I want you to cut the pyramid at the 20 mm distance. You will see that I draw a line at the center of the pyramid. This is the distance I want you to cut the pyramid at. the I want the two ends to be opened.

2- the second pyramid that has no circle around it. I want you to change the measurement to be ( box inside at bottom = 15 x 15 mm, box outside at bottom 21 x 21 mm, distance from center to the top 68 mm). convert to 3d modeling, then Cut the pyramid at distance 18 mm from the center of the pyramid.

Notice that the pyramid is no longer gonna be a pyramid after you cut it. but that is fine because we want to be more specific about angles. that is why at pyramid 1, the distance from center to the top of the pyramid is 100 mm, and 68 for the second pyramid. you will see that I have a 3d solid with the two design. that was my practice but I failed because the angles did not change between top and bottom. If you are good with Autocad this should take you less than two hours. I could not upload the file but I can email it to you.

make sure you are allow to work with Autocad. Thank you,