Rendering - error message re: faces

[jtho]

I have a model of a window consisting of solids extruded from plines that I am trying to render. When I go to render it, I get an error message saying "No Faces to render, Halting Render." When this happens, I can occasionally switch back from my camera view to an isometric view, scroll in and out at random, and it will render my camera view. If I try to render it a second time, without changing anything, I get the error message again. Most of the time, I just get the error message no matter what I try. The view through the camera is correct, I've tried positioning lights from all angles, and I can even adjust the color of the faces that the camera is viewing, so I can't figure out what the problem is. I don't know that it makes a difference with solids, but I drew my plines in a counterclockwise direction on the XY plane and have tried rendering with the "back face normal is negative" option both on and off. Anyone run into this before?

[jtho]

After wrestling with this for far too long and missing a deadline, I've stumbled over the fix. I will post it here for a bit in case anyone is curious or has had the same problem, then delete this topic.

The objects I was trying to render were on layers whose names began with the "@" symbol. I had started with some inherited elevations I was projecting off of and had named my layers in this manner so that they appeared at the top of the list in the layer manager and I could find them quickly to work with. AutoCAD didn't seem to have a problem with this in any other way. As soon as I took the "@" symbol out of the name, I have had no problem with rendering. How this relates to faces I cannot fathom...

For what it's worth, I am using AutoCAD 2002.

[csiarch]

Layers will appear at the top of the list if the name starts with a number. If planning to use more that nine layer names, use a leading zero. Ex. "01layername", "02layername" and so on.

When displaying lists, computers will list text strings starting with numbers before listing those starting with alphabetic characters....been this way since the start.

It ain't rocket science but I name layers with 3d objects on them "3Dlayername". :roll:

[VERYCIVILDRAFTER]

To expand on what csiarch said...

You should consider only using the very basic alphanumeric characters that were acceptable for layers in the R14 and earlier days. It's very restrictive, but if you stick to only these characters you can save lots of headaches in software that runs with AutoCAD as a base.

I jumped into my dusty R14 (just for you) and this is the list IN ORDER of available characters. This also means No SPACES and No Lowercase.
$
- (dash)
0-9
A-Z
_ (underscore)


Dash is my personal favorite for layers I want at the top of the list, but the dollar sign is the Ace High Straight Flush.

[csiarch]

This is kinda' far out but I'm wondering if using the "at" (@) symbol in layer names somehow sent the rendering routine off in search of something to render along a vector.....like the standard syntax for distance/direction???? The error message he got said something about not finding a surface...or something like that???

Maybe an AutoCad BUG? WHAT? WHO SAID THAT? :shock:

BTW, VCD: Nice research. My release 14 will NOT do all uppercase layer names no matter what. This feature is usually linked to O/S system settings (as for file names) but it makes no difference. It always defaults to 1st letter CAPS, the rest lowercase. -or all lower case. Think AutoCad probably converts to all U/C internally -like DOS does.

[VERYCIVILDRAFTER]

That's an interesting thought csiarch, because the $ sign is used in lisp.

e.g. $(getvar,<some variable>)

I wonder if having the $( as the beginning of a layer name could cause confusion for lisp that works with layers?

[csiarch]

VCD: I don't have a clue but I've seen stranger things happen in other software. It's almost like the programmers assume that NO ONE would EVER use such characters so they don't build any I/O routines to take care of it if someone comes wondering by and tries it.

Drawing from my own minimal experience writing programs, I recall spending most of the time writing I/O routines to handle miskeying and stupid attacks. :roll:

My guess is that AutoCad developers are probably all flaming liberalists: "We know what software is best for you; don't bother us with improvement suggestions!" :?

[jtho]

csiarch & VCD, thanks for the suggestions regarding characters acceptable to AutoCAD (and, VCD, for the dusty research)! I haven't any real experience with LISP routines and the extent of my programming goes back to some BASIC and a wee bit of C++ back in the day, so it's interesting to hear some ideas about the basis of the problem...

[VERYCIVILDRAFTER]

You're right about R14 and the Uppercase Lowercase names... I don't know what I was thinking about there. :?

I would still consider using some kind of standard for character case. In bigger companies there are lots of people to try and stretch the rules any where they can, but some things are not worth the cost of battle.