How to display full 3D region?

Answers to an earlier posting, ConvexHullMesh inconsistency, have let me construct a particular 3D region by intersecting a pyramid with a halfspace:

Rint = RegionIntersection[Rhalfspace, RPyramid] 

The construction is correct, and the region displays like this upon executing the above command:


The slanted plane is (correctly) caused by `Rhalfspace`. The two vertical planes are caused by some type of plotrange clipping. My question is simple:

Q. How do I display the full region?

I’ve tried RegionPlot3D, DiscretizeRegion, but nothing I try allows me to e.g., use PlotRange. I am missing something basic about how to convert a region to a 3D graphics object.

I know I should include code for experimentation, but perhaps there is just a simple generic method to convert a 3D region to Graphics3D so that I can use the options to Graphics3D.