#DXF Reader
3 messages in this thread
Hi Nick:
In one of your recent messages to someone, you stated that the latest revision
(July) to Renderize included some minor changes to the DXF reader. Perhaps you
can tell me if this will improve the import of DXF files from Upfront with
respect to normal direction.
I create all my models in Upfront and have been making the extra effort to
orient the normals in a specific direction and then making them one-sided for
display purposes. This speeds up the display within Upfront. I then naturally
thought that when I imported a DXF version of a model into Renderize, I would
not have to go through the tedious process of reversing normals.
Unfortunately, this is not the case. I don't know if the problem is Upfront's
DXF export, Renderize's import, or if the DXF standard does not pay any
attention to normals.
Do you have any suggestions?
-Richard
Richard:
Which version of Upfront are you using? I believe that the dxf files from v1.1
come out somewhat better than those of the original release. I know this takes
more time but I usually turn on the backfaces of all geometry right after I
load into Renderize.
I noticed another thing in Upfront, the "Make 2-sided" option in Upfront shifts
the faces and can often make the normals come out just right on certain
objects.
Hope this helps.
joel*
Many file formats don't have explicit information about polygon normals. Some
use the implicit method that derives a normal from a perpindicular between two
edges of a polygon, however, some programs use different sets of edges to
determine that normal. (For example, one program might use the first two edges
in a polygon, another might use the first edge and the last edge.) Another
problem with programs that export to DXF is that they need dto be very careful
when turning a multi-sided polygon into triangles or quads for DXF's 3DFACE
entities, because if they aren't careful about normals, you'll see each polygon
turn to "swiss cheese" in destination 3D programs that are sensitive to
normals.
My company makes InterChange, a program that translates between many different
3D file formats. If you have any translation questions, I'd be glad to help.