ARMAN, Mr. Reyes and The Magic of the Metric

ARMAN, Mr. Reyes and The Magic of the Metric

About six weeks ago, I posted a question about the splitting loop in REYES.
More specifically about it's description in ARMAN. Now, 2:25 AM in The
Netherlands, sitting in bed with my sister's laptop, while roaming the
Google group archive looking for anything REYES I realized that I hadn't got

So, I'll try again:

In Advanced Renderman in the chapter describing REYES there's a section on
the splitting loop. In this section it says
"If the primitive is (at least partially) on-screen, its size is tested. If
it is deemed "too large" on-screen, according to a metric described later,
it is split into smaller primitives. [...]"

What is that metric and where is it described?
I've been reading chapter 6 dozens of times now, but I can't put my finger
on the thing, I'm desperate to know.... BOOOOOHOOOOOOO!!!

Trinity: I know why you're here, Leo. I know what you've been doing... why
you hardly sleep, why you live alone, and why night after night, you sit by
your computer. You're looking for Mr. Reyes. I know because I was once
looking for the same thing. And when I found him, he told me I wasn't really
looking for him. I was looking for an answer. It's the question, Leo. It's
the question that drives us. It's the question that brought you here. You
know the question, just as I did.
Leo: What is the Metric?
Trinity: The answer is out there, Leo, and it's looking for you, and it will
find you if you want it to.

Oh god, I'm getting too silly :)

Regards,
Paul
(who's starsign is Leo)

--
Paul Melis. Pondering if Tom Duff thinks up and types in one of his "unique"
signatures
by hand every time he posts in the group...

ARMAN, Mr. Reyes and The Magic of the Metric

: it is deemed "too large" on-screen, according to a metric
: described later, it is split into smaller primitives. [...]"
:
: What is that metric and where is it described?
: I've been reading chapter 6 dozens of times now, but I can't put
: my finger on the thing, I'm desperate to know.... BOOOOOHOOOOOOO!!!

I'm certainly not an expert, but I believe when the primitive is
smaller than a pixel (effectively called a
micro-primitive/polygon), it is sufficently small enough.

Kawaldeep

if you desire to correspond via email, please replace berzerkeley with berkeley

ARMAN, Mr. Reyes and The Magic of the Metric

>In Advanced Renderman in the chapter describing REYES there's a section on
>the splitting loop. In this section it says
>"If the primitive is (at least partially) on-screen, its size is tested. If
>it is deemed "too large" on-screen, according to a metric described later,
>it is split into smaller primitives. [...]"

>What is that metric and where is it described?

The metric is: if you were to dice the primitive into little quads
whose size is given by the shading rate, would you get "too many"
of those quads?  Where "too many" is a user parameter ("gridsize" in
PRMan).

-- lg

--
Larry Gritz                                     Exluna

ARMAN, Mr. Reyes and The Magic of the Metric

>  : it is deemed "too large" on-screen, according to a metric
>  : described later, it is split into smaller primitives. [...]"
>  :
>  : What is that metric and where is it described?
>  : I've been reading chapter 6 dozens of times now, but I can't put
>  : my finger on the thing, I'm desperate to know.... BOOOOOHOOOOOOO!!!

> I'm certainly not an expert, but I believe when the primitive is
> smaller than a pixel (effectively called a
> micro-primitive/polygon), it is sufficently small enough.

No, you're thinking of "dicing", not "splitting". Splitting comes
first, and determines the size of each grid. After a primitive is
split, each part is sorted into the right bucket (i.e. the first that
intersects its screen-space bounding box). When that bucket comes up
for rendering, *then* the part of the split primitive will be diced
into micropolygons. The micropolygons are then associated with every
bucket they could possibly affect.

I know, it's confusing.

--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.

ARMAN, Mr. Reyes and The Magic of the Metric

Quote:>Trinity: I know why you're here, Leo. I know what you've been doing... why
>you hardly sleep, why you live alone, and why night after night, you sit by
>your computer. You're looking for Mr. Reyes. I know because I was once
>looking for the same thing. And when I found him, he told me I wasn't really
>looking for him. I was looking for an answer. It's the question, Leo. It's
>the question that drives us. It's the question that brought you here. You
>know the question, just as I did.
>Leo: What is the Metric?
>Trinity: The answer is out there, Leo, and it's looking for you, and it will
>find you if you want it to.

Follow the rabbit Leo, the white rabbit. And stay away from the pink pills, ya hear me ?
Or was it the blue one ? =P

doberlec

<include disclaimer.h>

ARMAN, Mr. Reyes and The Magic of the Metric

Quote:> >Trinity: I know why you're here, Leo. I know what you've been doing...
why
> >you hardly sleep, why you live alone, and why night after night, you sit
by
> >your computer. You're looking for Mr. Reyes. I know because I was once
> >looking for the same thing. And when I found him, he told me I wasn't
really
> >looking for him. I was looking for an answer. It's the question, Leo.
It's
> >the question that drives us. It's the question that brought you here. You
> >know the question, just as I did.
> >Leo: What is the Metric?
> >Trinity: The answer is out there, Leo, and it's looking for you, and it
will
> >find you if you want it to.

> Follow the rabbit Leo, the white rabbit. And stay away from the pink
pills, ya hear me ?
> Or was it the blue one ? =P

<trinnggg ....>
Leo: <click> Hello?
Trinity: My name's Trinity.
Leo: .... errr .... ah, the girl from the club two weeks ago, hi honey!
Trinity: That was a long time ago.
Leo: Oh come on, we had something good going on! I'd like to see you again.
Trinity: What?
Leo: No really, I had a good time with you.
Trinity: Most guys do.
Leo: ... <jawdrop> ... I can't believe you actually said that....
Trinity: Please Leo, you have to trust me.
Leo: I do, honey, I do! So, why you're calling?
Trinity: Because you have been down there Leo, you know that road, you know
exactly where it ends. And I know that's not where you want to be.
Leo: Wow, you're good.... yeah, I would like a bit more of a long-term
relationship... All those one-night stands don't make you feel better in the
long run and <click>
Leo: Hello? Hello? Trinity? .... damn!

Agent Brown: She got out.
Agent Smith: Doesn't matter.
Agent Brown: The informant is real.
Agent Smith: Yes.
Agent Jones: We have the name of their next target.
Agent Brown: The name is Leo.
Agent Smith: We'll need a search running.
Agent Jones: It has already begun.

<tringggg .... tringgg>
Leo: <click> Hello?
Morpheus: Hello, Leo. Do you know who this is?
Leo: Mom?
Morpheus: Far from it.
Leo: Errr.... Wendy?
Morpheus: Far from it.
Leo: I give up...
Morpheus: . I've been looking for you, Leo. I don't know if you're ready to
see what I want to show you, but unfortunately, you and I have run out of
time. They're coming for you, Leo, and I don't know what they're going to
do.
Leo: Who's coming for me?
Morpheus: Stand up and see for yourself.
Leo: What, right now? I'm under the sink trying to fix a leakage!
Morpheus: Yes, now.
Leo: Okay...
<KLUNK>
Leo: Shit, that hurts! ........ Well, nothing to see here. You sure you got
the right person?
Morpheus: You have the look of a man who accepts what he sees because he is
expecting to wake up. Ironically, that's not far from the truth.
Leo: Hmmm, I'm not expecting to wake up much more today. Boy, my eyes
hurt...
Morpheus: You've never used them before.
Leo: .... no, you idiot, it's part of the hangover of yesterdays drinking
binge! Oh yeah, and I smoked to much.
Cypher: Good shit, huh? It's good for two things: degreasing engines and
killing brain cells.
Leo: What? Who was that?
Morpheus: I imagine that right now you're feeling a bit like Alice, tumbling
down the rabbit hole.
Leo: Close, more like a rabbit tumbling down Alice's hole.
Morpheus: Welcome to the desert of the real.
Leo: Pfff, this is all getting a bit too real for me. Wish it was holidays
again...
Morpheus: What is "real"? How do you define "real"?
Leo: Oh man, stop giving me a hard time on a saturday morning, my head's
hurting already! Maybe some coffee will get me started...
<flush, sizzle, <yawn>, klunk, click ..... click click>
Leo: ...... Helloohooh? Are you gonna make me coffee or what? Stupid
machine...
<click .... click .... click click click>
Leo: Damn, it's broken!
Morpheus: Throughout human history, we have been dependent on machines to
survive. Fate, it seems, is not without a sense of irony.
Leo: Is that supposed to make me feel better or what?
Morpheus: You have to let it all go, Leo. Fear, doubt, and disbelief. Free
Leo: I'd sure like to let something go free right now, you're getting on my
nerves!
Morpheus: Stop trying to hit me and hit me!
<SMACK!>
Morpheus: ouch
Rhineheart: You have a problem with authority, Mr. Melis.
Leo: ARRRGGGG!!!! Mr. Wizard! Get me the hell out of here!

ARMAN, Mr. Reyes and The Magic of the Metric

Gettin' a little goofy from all the late-night rendering, guys? ;)

Hello folks,

In Advanced Renderman in the chapter describing REYES there's a section on
the splitting loop. In this section it says
"If the primitive is (at least partially) on-screen, its size is tested. If
it is deemed "too large" on-screen, according to a metric described later,
it is split into smaller primitives. [...]"

But I can't find a description of the mentioned metric (or at least the
section that it's probably referencing). Now that I think more about it,
there's no talk about a primitive's size when bucketing is discussed. Is the
outcome of the "split-necessary?" test determined by wether a primitive fits
in a bucket (or more precisely if it's bounding box after projection in
screen coordinates is smaller in dimensions than a bucket's size)?