Ever since I got back into town and saw RLG1034's posting "aaargh," I've been thinking about pyramids. Teri's formula approach got me very confused, so I built my shader out of Eric Winemiller's bricks shader element. I had to build the pyramid in four sides, though, using cube face mapping to get the bricks to line up properly. Once I did that, I just had to make a pic. Anybody else driven to Egyptian things? (Or Alan Parsons Project songs -- if anybody gets the reference....)

Very cool Sky! I love Alan Parsons. I don't know what his claim to fame is other than the music.

I don't remember Alan Parsons, I lost interest in music long before he came on the scene. I'm closer to those pyramids! looks good AzChip, & yeah, Egyptian things are cool.

Oh Yeah, now I remember the pyramid fetish/fads. That was around the time that I was "U.S. Property" & that kind of music wasn't available on the radio in Texas where I was stationed (yes, it was a different country). If I was lucky I could get WLS out of Chicago late at night.

Chip, I think your pyramids look better than mine, as the formula I used didn't really work at the corners (it was more a formula experiment than a serious pyramid attempt).

First, to On-topic stuff -- Teri, I tried using your formula in my shaders; all it gave me was a very pretty rainbow effect. Very nice, and I'll likely be using that for another project I'm working on, but it didn't look much like a pyramid. (Except for those that I used to look at in the seventies when such odd colorations were expected. Although I'm not sure if the colorations were really in the posters or just in my mind....) Then, on to Alan Parsons: He was an assistant engineer on the Beatles Abbey Road album, but won a Grammy for his engineering work on Pink Floyd's Dark Side of the Moon. He also invented the analog precursor to the sampler; it was called the Projectron and could play tape loops at varying speeds depending on what key you pressed. I lived in Texas (though I wasn't US Property at the time) about twelve years ago. You're right, Willf; it's a different country. Lots of Cheddar, though....

Hmm, the default formula is a rainbow effect. Did you hit the Parse button after making changes? Here's a Pic of my shader (keep in mind that some of the formula is cut off).

Very good AZ... All answers correct... You get to move on to the final round ! :)

Hmmmm.... Well Terri, I tried it again to no avail. Of course, I'm using RDS, so maybe that's some of the problem. I did click the parse button, too.... I'm frightened by the math, anyway, so maybe it's just as well.... But thanks for the screen shot. I'll have to try it again. And CCP -- bonus points for you if you can name Alan Parsons' studio.

Well, for all I know RDS formulas could be very different. If you really want to mess with formulas (and I've only scratched the surface) I'd start with something simple like plain ol' stripes, first. You can do this with a one line formula in Carrara: red=z-floor(z); (z is the vertical position, floor(z) is the next lowest integer, or at least that's what it is in Carrara).

Here is a pyramid shape formula, adapted from the SuperEllipse. Can make cones, cubes, pagodas, cylinders and, oh yeah, pyramids.

s=PI*(u-0.5); t=2PI(v-0.5); a=cos(s); b=cos(p3t); c=sin(t); d=sin(s); i=p110; j=p210; M=((a>0)?pow(a,i):-pow(-a,i)); N=((b>0)?pow(b,j):-pow(-b,j)); Q=((c>0)?pow(c,j):-pow(-c,j)); R=((d>0)?pow(d,i):0); x=5MN; y=5MQ; z=5R;

You get a pyramid at p1, p2 = .2 and at p1 = .2, p2 = 0. SMcQ

Nice! Looks like I need to give the formulas a deeper look. --Terri