| |
(Note: Please follow-up to ".cad.dev".)
In lugnet.cad.dat.parts, Tony Hafner writes:
>
> What is an optional line? These seem to be used for modeling curves,
> but I don't have a clue how to use them.
OK, first you need to bear in mind that LDraw does _NOT_ draw
true curves, it draws _angles_. If you have enough angles
in a line, from a sufficient distance, this angled line
will _appear_ to be a true curve.
Now, with regards to "conditional" (i.e., type-"5") lines,
think about the 3-D ramifications of using multi-angled planes
to simulate a curved plane (the 3-D extrapolation of the 2-D
principle of using angles for curves mentioned above).
A "true" curved plane doesn't really have "edges"
(with regards to its curvature, that is), but when using
these angled planes, sometimes one of the folds of the angled plane
will also be an edge of the model/shape itself.
For example, imagine the ubiquitous D20, a 20-sided die.
Let's pretend we're using this to _simulate_ a sphere.
A true sphere has a circular "edge" line (which we could call
a horizon, perhaps), but the d20 does not have a nice, neat
circular border, does it? Depending on which two points
you're holding it by, and which face(s) are pointing towards you,
that determines which of the actual edge-lines would need
to be drawn in order to simulate our horizon.
Does this help any?
> While I'm asking, what is a BFC statement?
"BFC" = "Back Face Culling", something about deleting/not rendering
the "back faces" (i.e., the sides concealed by the rest of the model,
or otherwise not viewable). Someone else will have to explain better,
this is as much as I understand about BFC.
Franklin
|
|
Message has 2 Replies:
 | | Re: Question about generating curves
|
| ----- Original Message ----- From: "Franklin W. Cain" <fwcain@yahoo.com> To: <lugnet.cad.dat.part...gnet.com>; <lugnet.cad.dev@lugnet.com> Sent: Tuesday, January 09, 2001 9:38 PM Subject: Re: Question about generating curves (...) Back faces are (...) (24 years ago, 10-Jan-01, to lugnet.cad.dev)
| | | Re: Question about generating curves
|
| In lugnet.cad.dat.parts, Franklin W. Cain writes: <snip> (...) <snip> (...) Franklin, Your quite a humorus man. What the hell did you just say! Please allow me to explain why I'm laughing. I didn't graduate high school, I don't have a GED but even (...) (24 years ago, 10-Jan-01, to lugnet.cad.dev)
|
Message is in Reply To:
| | Question about generating curves
|
| What is an optional line? These seem to be used for modeling curves, but I don't have a clue how to use them. While I'm asking, what is a BFC statement? Um... and why does MLCAD use a German-localized cancel button for the BFC statement dialog? -- (...) (24 years ago, 10-Jan-01, to lugnet.cad.dat.parts)
|
9 Messages in This Thread:
 
  
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
This Message and its Replies on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
