Logo by Maya - Contribute your own Logo!

END OF AN ERA, FRACTALFORUMS.COM IS CONTINUED ON FRACTALFORUMS.ORG

it was a great time but no longer maintainable by c.Kleinhuis contact him for any data retrieval,
thanks and see you perhaps in 10 years again

this forum will stay online for reference
News: Follow us on Twitter
 
Home Help Search Gallery Downloads Login Register
*
Welcome, Guest. Please login or register. October 01, 2018, 02:45:57 PM


Login with username, password and session length


The All New FractalForums is now in Public Beta Testing! Visit FractalForums.org and check it out!


Welcome to Fractal Forums > Fractal Software > Help & Support > Rendering part of a plane
Pages: [1]   Go Down
« previous next »
  Print  
Share this topic on DiggShare this topic on FacebookShare this topic on GoogleShare this topic on RedditShare this topic on StumbleUponShare this topic on Twitter
Author Topic: Rendering part of a plane  (Read 348 times)
Description: Using intersections of distance functions.
0 Members and 1 Guest are viewing this topic.
Imagyx
Navigator
*****
Posts: 72


Finally 3D and more... Thank you !! ;-)
« on: August 29, 2017, 09:23:07 PM »
Hi.
I'm using the 4 functions from
http://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm

When using "Intersection" with ""Sphere - signed - exact" and "Plane - signed - exact" I get  only the part of the sphere intersecting the plane.
But it doesn't work with "Box - signed - exact". I get nothing out of it.
Why ?
Box and Plane are visible and definitively intersecting, when rendering both.
And the sphere with the same 'radius' as the cube works...  huh?

Thank you for any hint  smiley
Logged
During difficult times, keep steady and play the match.
claude
Fractal Bachius
*
Posts: 563



WWW
« Reply #1 on: August 29, 2017, 10:10:39 PM »
works for me  huh?

see attached...

* de-test.gif (204.62 KB, 128x128 - viewed 67 times.)
* de-test.frag.txt (2.1 KB - downloaded 14 times.)
Logged
Imagyx
Navigator
*****
Posts: 72


Finally 3D and more... Thank you !! ;-)
« Reply #2 on: September 06, 2017, 09:54:33 PM »
Isn't this part of a box, therefore 3-dimensional ? I just want a part of the plane, which is 2-dim...
Maybe I misunderstood something, because after doing some tests, it seems that with
intersecting box and plane I get one of the two parts of the box, which is cut by the plane.
And these tests also revealed, that it's the same with a sphere, I just didn't see it before by chance.
Example picture here:

* P3D_2017.09.06_21.52.49.png (19.31 KB, 600x400 - viewed 15 times.)
Logged
During difficult times, keep steady and play the match.
claude
Fractal Bachius
*
Posts: 563



WWW
« Reply #3 on: September 07, 2017, 03:20:40 PM »
in the distance estimation,  the "plane" is really a half-space, which is solid on one side.

the problem with truly 2D things in 3D distance-estimation is that they have 0 thickness, which means rendering algorithms can error by going straight through them or require adjusting fudge factors to make everything thicker.

maybe you really want a double-sided plane with a small thickness, which could be made by intersecting two opposing parallel half-spaces that are close together (but not coincident).
Logged
Imagyx
Navigator
*****
Posts: 72


Finally 3D and more... Thank you !! ;-)
« Reply #4 on: September 09, 2017, 12:25:25 PM »
Thank you very much, claude  smiley
Thickness is indeed needed for the DE to work and
your suggestion to intersect two half-spaces works for me.
I can make the Plane much thinner than it is in the video (see below)
and project an image onto the plane which is why I even needed a plane and not a simple box where the image would be wrapped around.
Have a nice weekend. With this I definitely have mine  wink
* SphereCut.avi (101.39 KB - downloaded 8 times.)
Logged
During difficult times, keep steady and play the match.
Pages: [1]   Go Down
« previous next »
  Print  
« previous next »
 
Jump to:  

Related Topics
Subject Started by Replies Views Last post
tilting the mandelbrot 2d plane Introduction to Fractals and Related Links tobiles 4 857 Last post May 22, 2012, 11:10:19 AM
by Sockratease
Still life at the Asymmetry plane Mandelbulb3D Gallery KRAFTWERK 0 139 Last post August 13, 2012, 05:58:35 PM
by KRAFTWERK
Weird Rendering - 2D plane appeared Mandelbulber Gallery mclarekin 0 163 Last post June 08, 2013, 04:12:19 AM
by mclarekin
Ships rising from the plane Images Showcase (Rate My Fractal) youhn 1 425 Last post May 03, 2015, 03:41:11 PM
by Pauldelbrot
First vs.Second Focal Plane Images Showcase (Rate My Fractal) thom 0 283 Last post May 15, 2016, 06:40:18 AM
by thom

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines

Valid XHTML 1.0! Valid CSS! Dilber MC Theme by HarzeM
Page created in 0.136 seconds with 26 queries. (Pretty URLs adds 0.012s, 2q)