here is the way i look at the topic you are asking about-
a DWG wireframe model can come from many different modelling
programs.. it's like an artist's sketch of something that you
can build in revit.. but it's not anything that can actually
be used as part of a revit model.. it's just for reference..
if you are going to change any materials to the import layers-
the best is an off white for all of them- so you can render it and
see better the shape of its parts.. remember the whole imported
mass DWG is for reference only.. and it's a better idea to
import that DWG as a mass into a SEPARATE session of
revit- (DWG lines mix in a revit project like oil mixes
if you are trying to see better the different parts of that
mass by turning layers on and off- a better way is to
section-box it or use an elevation clip line or cut it at
a certain depth in plan view- sections etc. etc.
i use the measure tool only and measure parts of it as i
build it in my revit project.. i also constantly use the
windows snipping tool and import the image into
my project to create revit elements accordingly.. you
adjust the image to scale and of course you have to
make sure you get the DWG import scale correct
in the first place.. i always import black lines only..
but you might change those line colors to see your imported
image snippets better..
i know autodesk is now marketing the massing part
of revit as a separate stand-alone program for design
artists- but most designs come from a .skp or a .dwg..
i guess the big idea with revit massing is that you can
use the "building maker" tools and place walls on the
massing lines- but that don't make much sense to me
because massing is just a conceptual sketch and the
lines are not precise enough for walls at that stage..
so it's really the same as a DWG mass import as far
as i can see.. but still i don't use revit massing to
be saying too much about it.. i always considered
revit to be a virtual construction and documentation
program- rather than a design program.. however
after seeing the flood of artists going for revit and
posting their designs in the gallery- i guess revit
is for design too..