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Best way to make a solid out of points that enclose a volume of space?
First of all - apologies for my ignorance. I am an electrical engineer and mostly use AutoCAD for 2D schematics/wiring diagrams. I am not very familiar with the 3D tools, and I am certainly not qualified to use them. Thanks for your help.
Short version of my question: I have some 3D points in space which, together, completely enclose a volume of space. I want to make that enclosed volume into a 3D solid. What is the most efficient way to do this?
Long version of my question (with additional info about what I am trying to do in case anyone has good advice) :
I have a hill with a steep slope that I want to terrace and make into gardens. I decided to do a 3D model of the hill to figure out the best way to terrace it before I start digging, and calculate how much fill I will need. So took some measurements of the hill which are basically like a GIS point cloud, except I measured them manually and the point density is pretty low. But its good enough for my purposes.
So now I have all these 3D points representing the surface of the hill. Below them I defined a reference plane which is the elevation of the bottom of the hill. I now want to make a complex 3D solid which fills in all the volume between the surface of the hill and the reference plane below. I will then use subtractions and other modifications to explore different ways to terrace the hill.
To make the 3D solid, I first connected each point to the adjacent points with lines. This creates a mesh like surface with triangular facets. I then project the triangular facet onto the reference plane below. This gives me 6 total points in space - 3 in the plane of the reference plane, and 3 more at various elevations above the refence plane. Together those 6 points completely enclose a 3D volume which is like a triangular bar with one end cut at an angle.
My plan was to create each of those solids individually and then union them all together to make the final solid model of the hill.
The problem I am having is it is very hard and time consuming to make each solid, and at this rate even with the low point density its going to take me a couple of days of highly repetitive work to make the solid. There HAS to be an easy way to do this, right? I would expect there to be a simple command where you choose either points in space or lines in space that enclose a volume and AutoCAD makes a solid out of the volume. It seems like that would be the easiest way to make irregular/odd shaped solids.
Looking through the documentation, I think that possibly SURFSCULPT might do what I want to do, but it doesn't seem to be available in my version of AutoCAD (2012 MEP).
I tried extruding the 2D facets, but that doesn't give me a solid. It gives me a shell made out of surfaces open on both ends. All attempts to convert those surfaces into a solid failed. Maybe I am doing it wrong? I tried manually enclosing both ends with an additional surface to make a 6 sided figure, but still wont convert them to a solid.
The only way I have figured out to do it so far is to insert a cylinder or other 3D solid which is larger than my desired solid, then use the 3D points to as cutting planes for the slice command to cut the solid down to size. This works, but is very time consuming as each solid requires 4 slices.
Below is a screen shot of my work so far. The white rectangle is the reference plane. The green solid is one that I have made using the cylinder-slice method. The point mesh is my hill, and the yellow lines are the projection of a facet onto the reference plane, showing the volume I want to make into a solid.
Thanks for any help!