Results 1 to 10 of 10

Thread: Node setup to render both sides of a polygon? (while 'double sided' is UNchecked)

  1. #1
    Registered User MrFurious's Avatar
    Join Date
    Jun 2006
    Location
    Melbourne
    Posts
    161

    Node setup to render both sides of a polygon? (while 'double sided' is UNchecked)

    Wonder if it's possible to have LW render both sides of a poly even if the 'double sided' flag in the main surface editor is unchecked?

  2. #2
    TrueArt Support
    Join Date
    Feb 2003
    Location
    Poland
    Posts
    7,900
    When renderer is checking ray-triangle intersection the first thing it's doing is checking whether there is double sided flag in surface..
    If it's cleared, ray is passed through without incrementing ray recursion counter, and hitting ray recursion limit.
    Any evaluation of nodes, would require incrementing ray recursion.
    So no, it would be bad idea. It would slow down rendering.

  3. #3
    Registered User MrFurious's Avatar
    Join Date
    Jun 2006
    Location
    Melbourne
    Posts
    161
    So therefore having the surface as double sided, weather it be through nodes or the surface editor checkbox, would effectively have the same impact on the render engine in terms of ray recursion etc?

    If that's the case and there's no difference.. I'd like to find a way to do it via nodes. This is because having high density poly objects in layout with double sided surfaces slows down openGL performance a lot. If I UNcheck all the double sided flags for all surfaces for all objects the openGL performance gain is huge. Then (if possible) I could setup double sided in the node editor but only for those surfaces requiring it.

    I found generally scenes render faster when the double sided checkbox is cleared
    Last edited by MrFurious; 07-24-2015 at 09:47 PM.

  4. #4
    TrueArt Support
    Join Date
    Feb 2003
    Location
    Poland
    Posts
    7,900
    It would be possible to make plugin which is setting/clearing double sided for all objects all surfaces, in one key press.

    If I UNcheck all the double sided flags for all surfaces for all objects the openGL performance gain is huge.
    Exactly twice.

    That's why this feature is default off..

  5. #5
    Registered User MrFurious's Avatar
    Join Date
    Jun 2006
    Location
    Melbourne
    Posts
    161
    Quote Originally Posted by Sensei View Post
    It would be possible to make plugin which is setting/clearing double sided for all objects all surfaces, in one key press.
    I think that's already possible without plugins, just select all surfaces and uncheck DS? Unless I'm misunderstanding you.

  6. #6
    TrueArt Support
    Join Date
    Feb 2003
    Location
    Poland
    Posts
    7,900
    But you have to go to Surface Editor, toggle By Objects, select all surfaces, then toggle.
    I am talking about press Layout Generic button "Double Sided All" or "Double Sided None" and voila.

  7. #7
    Axes grinder- Dongle #99
    Join Date
    Jul 2003
    Location
    Seattle
    Posts
    14,732
    Quote Originally Posted by MrFurious View Post
    Wonder if it's possible to have LW render both sides of a poly even if the 'double sided' flag in the main surface editor is unchecked?
    I'm pretty sure, like Sensei says, you wouldn't get any render speed advantage, as the same operations would have to be performed to make it render correctly.

    Unless you have a very special situation where you want some rays to ignore one side of a poly and not the other.

    Why would you want this?
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  8. #8
    Registered User MrFurious's Avatar
    Join Date
    Jun 2006
    Location
    Melbourne
    Posts
    161
    I always use toggle by objects anyway so really it's only 3 clicks for me. But actually I need to have double sided rendered in F9/VPR for some objects like tree with many leaves, but at the same time not have them as double sided in openGL.

    - - - Updated - - -

    Not wanting a render speed advantage but an openGL speedup

  9. #9
    Axes grinder- Dongle #99
    Join Date
    Jul 2003
    Location
    Seattle
    Posts
    14,732
    Ah. Yep, that would be a very valid work-around. ---Of course, a proper OGL implementation would be even nicer.
    They only call it 'class warfare' when we fight back.
    Praise to Buddha! #resist
    Chard's Credo-"Documentation is PART of the Interface"
    Film the cops. Always FILM THE COPS. Use this app.

  10. #10
    Super Member Kevbarnes's Avatar
    Join Date
    Nov 2006
    Location
    Gloucestershire UK
    Posts
    509
    Quote Originally Posted by MrFurious View Post
    This is because having high density poly objects in layout with double sided surfaces slows down openGL performance
    You could try saving a 'Surface Library' of your objects. one with all surfaces single sided
    plus a library with chosen surfaces double sided - one RgtClick then Load surface ................ ok, its 2 operations!

    but you would be able to swap-out at will
    "one rig to rule them all"
    PC Spec: Intel i7 X980 3.33GHz | 24Gb | ATI FirePro V5800 | W7
    https://vimeo.com/kevbarnes/showreel
    https://littlstar.com/kevbarnes
    https://www.talenthouse.com/kevbarnes

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •