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"Bald Eagle" <cre### [at] netscapenet> wrote:
> Because my kid was watching a Bob Ross video:
>
> https://towardsdatascience.com/bot-ross-teaching-a-computer-to-paint-f5a9c9ef908
>
> :)

After a quick read though, I think the Bot should have watch more shows :)

[Leroy] Re: New random distribution macros [34 minutes ago]

2021-03-06 01:25:00 UTC

"Bald Eagle" <cre### [at] netscapenet> wrote:

I've done the  VRand_ON_Box (RandSeed) awhile ago for my MeshTree project
along with VRand_ON_Cone,VRand_IN_Cone, VRand_ON_Cylinder, VRand_IN_Cylinder

I used them to place the end points of a binary tree.

When I looked back on them  I found that the Cone marcos use a cone with a base
pov unit from <0,0,0,> the end point 1 unit in opposite direction 1 with the
base radius 1 and the other radius 0 and you had a choice of 3 directions to
place it
(x,y,z). The On_Cone also had the OPEN option.
 The cylinder macro has the same basic lay out.

They work great for making trees but I don't know if they have an even
distribution.
Here they are copied from the modified rand.inc I use.

//a random point ON a square box {-1, 1}
#macro VRand_On_Box(R)// LR added
 #local V=<0,0,0>;
 #local a=int(rand(R)*6);
 #switch (a)
  #case(0)#local V=<-1,rand(R)*2-1,rand(R)*2-1>; #break
  #case(1)#local V=<1,rand(R)*2-1,rand(R)*2-1>; #break
  #case(2)#local V=<rand(R)*2-1,-1,rand(R)*2-1>; #break
  #case(3)#local V=<rand(R)*2-1,1,rand(R)*2-1>; #break
  #case(4)#local V=<rand(R)*2-1,rand(R)*2-1,-1>; #break
  #case(5)#local V=<rand(R)*2-1,rand(R)*2-1,1>; #break
  #end
  (V)
#end

//a random point ON a Cylinder from -1 to 1 in the D direction
// radius=1
// if O open cylinder
// D=1 +y direction
// D=2 +x direction
// D=3 +z direction
#macro VRand_On_Cyl(D,O,R)// LR added
   #local Theta = 2*pi*rand(R);
   #local V=<0,0,0>;
   #local H=rand(R)*2-1;
   #local S=1; // radius
   #if(O) #local Hv=1;
   #else  #local Hv=.95;
   #end
   #if (H>Hv) #local S=rand(R);#local H=1; #end
   #if (H<-Hv) #local S=rand(R);#local H=0; #end
   #if (D=1)#local V= <H,cos(Theta)*S,sin(Theta)*S>; #end
   #if (D=2)#local V= <cos(Theta)*S,H,sin(Theta)*S>; #end
   #if (D=3)#local V= <cos(Theta)*S,sin(Theta)*S,H>; #end
  (V)
#end

//a random point IN a Cylinder from -1 to 1 in the D direction
// D=1 +y direction
// D=2 +x direction
// D=3 +z direction
#macro VRand_In_Cyl(D,R)// LR added
   #local Theta = 2*pi*rand(R);
   #local V=<0,0,0>;
   #local H=rand(R)*2-1;
   #local S=rand(R);
   #if (D=1)#local V= <H,cos(Theta)*S,sin(Theta)*S>; #end
   #if (D=2)#local V= <cos(Theta)*S,H,sin(Theta)*S>; #end
   #if (D=3)#local V= <cos(Theta)*S,sin(Theta)*S,H>; #end
  (V)
#end
//a random point ON a Cone from -1,1 to 1,0 in the D direction
// more values in the lower part
// if O open Cone
// D=1 +x direction
// D=2 +y direction
// D=3 +z direction
#macro VRand_On_Cone(D,O,RS)// LR added
   #local Rt=rand(RS);
   #local Rv=Rt*Rt;
   #local Theta = 2*pi*rand(RS);
   #local V=<0,0,0>;
   #local H=Rv*2-1;
   #local S=1-(H+1)/2;
   #if(H<-.95 & O=0)  #local S=rand(RS); #local H=-1;#end
   #if (D=1)#local V= <H,cos(Theta)*S,sin(Theta)*S>; #end
   #if (D=2)#local V= <cos(Theta)*S,H,sin(Theta)*S>; #end
   #if (D=3)#local V= <cos(Theta)*S,sin(Theta)*S,H>; #end
  (V)
#end
//a random point IN a Cone from -1,1 to 1,0 in the D direction
// more values in the lower part
// D=1 +y direction
// D=2 +x direction
// D=3 +z direction
#macro VRand_In_Cone(D,RS)// LR added
   #local Rt=rand(RS);
   #local Rv=Rt*Rt;
   #local Theta = 2*pi*rand(RS);
   #local V=<0,0,0>;
   #local H=Rv*2-1;
   #local S=1-(H+1)/2;
   #local S=S*rand(RS);
   #if (D=1)#local V= <H,cos(Theta)*S,sin(Theta)*S>; #end
   #if (D=2)#local V= <cos(Theta)*S,H,sin(Theta)*S>; #end
   #if (D=3)#local V= <cos(Theta)*S,sin(Theta)*S,H>; #end
  (V)
#end

[Bald Eagle] Re: New random distribution macros [4 hours and 54 minutes ago]

2021-03-05 21:05:06 UTC

"Kenneth" <kdw### [at] gmailcom> wrote:
> "Kenneth" <kdw### [at] gmailcom> wrote:
>
> > Voila! Well, discounting the mathematical magic that would probably be required.
> > ;-)
>
> I do see the main problem though, and it's a big one: How to correlate an
> oddly-shaped total 'area' of triangles on the TEXTURE map (certainly not a 1X1
> ratio area, and with an oddly-shaped perimeter) to the HF itself, which *is* a
> 1X1 ratio. It would be a strange scaling problem indeed.
>
> :-(

Well serendipity and synchronicity strike again:
I was looking for some info to better explain the meaning of the core inequality
in the polygon test, and I found a video by Sebastian Lague

https://www.youtube.com/watch?v=HYAgJN3x4GA

with this link in the comment section:

https://chrischoy.github.io/research/barycentric-coordinate-for-mesh-sampling/

[Bald Eagle] Re: in polygon tests [5 hours and 39 minutes ago]

2021-03-05 20:20:01 UTC

Thomas de Groot <tho### [at] degrootorg> wrote:

> You should do something about those midges.... ;-)

I took a cue from Robert and set the fireflies loose on them.   :P

[Kenneth] Re: Sci-Fi Scene Assets [8 hours and 19 minutes ago]

2021-03-05 17:40:01 UTC

"Robert McGregor" <rob### [at] mcgregorfineartcom> wrote:

>
> I don't think I've ever tried posting a video here before but I'm attaching a
> short MP4 clip of the animated engine media, hopefully it works.

Your final ship is really gorgeous, and the animation of the engine 'ion
exhaust' looks great! It's a nice and sophisticated use of media. Btw, thanks
for the description of your ship's surface texture; I had originally thought
that you had used one of POV-ray's newer 'pavement' patterns (perhaps that is
part of the mix), but your averaging(?) of simple box and rectangle
shapes/images makes perfect sense. I look forward to experimenting with that
technique.

Your work has really paid off! It's inspiring.

[As is usual with videos uploaded here-- at least through the newsgroups' web
portal-- the downloaded animation doesn't play in Windows Media Player, even
though it should. So I've learned to use a different media player app to play
it. I don't think the problem is with the added  .mp4  suffix here, whether left
as-is or removed; it seems that the upload/download process adds 'something' to
the file, or makes it different somehow. On my own Win 7 computer, I can play my
own animations in WMP; but when I upload them here, then download them, they
don't play. Weird.]

[Robert McGregor] Re: Sci-Fi Scene Assets [8 hours and 54 minutes ago]

2021-03-05 17:05:01 UTC

"Bald Eagle" <cre### [at] netscapenet> wrote:
> That's looking like a Firefly-class transport ship!    +1  :D

Thanks! Now that you mention it, there is a *slight* resemblance to the
Serenity. But she's more curvaceous :)

Thomas de Groot <tho### [at] degrootorg> wrote:
> VERY good, sir! I am awed by the way you just seem to shake this
> casually from your (admittedly ample) sleeve.

"Mr" <nomail@nomail> wrote:
> yummy eye candy!

Thanks Thomas and Maurice, this is a fun project, I'm glad you like it!

I don't think I've ever tried posting a video here before but I'm attaching a
short MP4 clip of the animated engine media, hopefully it works.

[Kenneth] Re: New random distribution macros [9 hours and 49 minutes ago]

2021-03-05 16:10:00 UTC

"Kenneth" <kdw### [at] gmailcom> wrote:

> Voila! Well, discounting the mathematical magic that would probably be required.
> ;-)

I do see the main problem though, and it's a big one: How to correlate an
oddly-shaped total 'area' of triangles on the TEXTURE map (certainly not a 1X1
ratio area, and with an oddly-shaped perimeter) to the HF itself, which *is* a
1X1 ratio. It would be a strange scaling problem indeed.

:-(