Quote: "Can you elaborate on this a little. How do you cut segment size openings out of a cave in Sketchup and how to you make the cave?"
If you hadn't switched on the sandbox tools in Sketchup, go to
Window>Preferences>extensions and tick the sanbox tools on.
Now draw a new terrain from scratch and use the smoove tool to mould some elevation to it. When satisfied, select all and reverse faces so the white side is inside(your cave)and the blue is outside.
Now draw a square about the base size of your cave, import a nice rock texture on the squere, set it to 'projected'(yeah it stretches when you made the walls to steep) and copy it to the bucket and paint your cave from the inside.
for the cuts model a box and place it so that it partly inside and partly outside the cave. now select both cube and cave and rightMenue to "intersect selected". Now delete what you don't need from the box inside the cave as well as the wall where the box will meet the next segment. Last but not least resize the Model with the tape measure tool so the box side will measure 2,54cm when exporting with the free plugin.
Quote: "the alien entities were awesome! where did you get them?"
Look for CosmicProphets Alien pack!
I am Jacks complete lack of surprise.