Anyone Knows the 3D volume iamge reconstruction from 2D slices?Thanks

I have 630 slices and I want to combine it into 3D volume image. Actually, I have use Cat(3,slice1,slice2) function to obtain the 3D array say, 512X512X630..

Q1.) The problem is that I have to set the thickness of every slice = 0.7 cm.. and obtain the Volume image like a cube. How to do that? I've used the 3D viewer before, however, It can only show the topview and cannot show the side view. The side view looks like many slices without thickness like this "||||||||"

I searched volume rendering,However, It would not work or Maybe I don't know to how to operate. Can anyone explain it clearly?

Thanks