From: Axel Kohlmeyer (
Date: Fri Jun 27 2014 - 22:07:49 CDT

how about this?

[akohlmey_at_zero ~]$ ~/lib/vmd/tachyon_LINUXAMD64 -h
Tachyon Parallel/Multiprocessor Ray Tracer Version 0.99
Copyright 1994-2011, John E. Stone <>
Unrecognized parameter/option flag: -h
  /home/akohlmey/lib/vmd/tachyon_LINUXAMD64 modelfile [options]

Model file formats supported:
  filename.dat -- The model files originated with this package. -- AC3D model files.
  filename.nff -- The NFF scene format used by Eric Haines' SPD.

Valid options: (** denotes default behaviour)
Message Options:
  +V verbose messages on
  -V verbose messages off **

Speed Tuning Options:
  -raydepth xxx (maximum ray recursion depth
  -numthreads xxx (** default is auto-determined)
  -boundthresh xxx (** default threshold is 16)

Shading Options:
  -fullshade best quality rendering (and slowest) **
  -mediumshade good quality rendering, but no shadows
  -lowshade low quality rendering, preview (and fast)
  -lowestshade worst quality rendering, preview (and fastest)

Lighting Options:
  -rescale_lights xxx rescale light intensity values by
                      specified factor (performed before other
                      lighting overrides take effect)
  -auto_skylight xxx force use of ambient occlusion lighting,
                      auto-rescaling direct light sources to
                      compensate for ambient occlusion factor.
                      (use value 0.7 as a good starting point)
  -add_skylight xxx force use of ambient occlusion lighting,
                      manually-rescaling direct light sources to
                      compensate for ambient occlusion factor.
  -skylight_samples xxx number of sample rays to shoot.

Specular Highlight Shading Options:
  -shade_phong Phong specular highlights
  -shade_blinn Blinn's specular highlights**
  -shade_blinn_fast fast approximation to Blinn's highlights
  -shade_nullphong disable specular highlights

Transparency Shading Options:
  -trans_max_surfaces xxx Limit the number of transparent
                           surfaces shown to the number specified
  -trans_orig Original implementation**
  -trans_raster3d Raster3D angle-based opacity modulation
  -trans_vmd Opacity post-multiply used by VMD

Transparent Surface Shadowing Options:
  -shadow_filter_on Transparent objects cast shadows**
  -shadow_filter_off Transparent objects do not cast shadows

Fog Shading Options:
  -fog_radial Radial fog implementation**
  -fog_vmd Planar OpenGL-like fog used by VMD

Surface Normal/Winding Order Fixup Mode:
  -normalfixup [off | flip | guess] (**off is default)

Antialiasing Options:
  -aasamples xxx (maximum supersamples taken per pixel)
                  (** default is 0, or scene file determined)

Output Options:
  -res Xres Yres override scene-defined output image size
  -o outfile.tga set output file name
  -clamp clamp pixel values to [0 to 1) (** default)
  -normalize normalize pixel values to [0 to 1)
  -gamma val normalize apply gamma correction
  -format BMP 24-bit Windows BMP (uncompressed)
  -format JPEG XXX Not compiled into this binary XXX
  -format PNG XXX Not compiled into this binary XXX
  -format PPM 24-bit PPM (uncompressed)
  -format PPM48 48-bit PPM (uncompressed)
  -format PSD48 48-bit PSD (uncompressed)
  -format RGB 24-bit SGI RGB (uncompressed)
  -format TARGA 24-bit Targa (uncompressed) **

Animation Related Options:
  -camfile Animate using file of camera positions.
  -nosave Disable writing of output frames to disk
                        (only used for doing real-time rendering)

Interactive Spaceball/SpaceNavigator Control:
  -spaceball Enable Spaceball/SpaceNavigator camera flight
  -spaceballport serialportdevicename (only for serial devices)

On Fri, Jun 27, 2014 at 7:54 PM, Tristan Croll <> wrote:
> The deadly combination of laziness and curiosity strikes again!
> One further question: is there a good listing of all the available switches
> for Tachyon available. It's the best renderer I think I've ever come across,
> but online documentation seems relatively sparse.
> Thanks,
> Tristan
> Tristan Croll
> Lecturer
> Faculty of Science and Technology
> Institute of Health and Biomedical Engineering
> Queensland University of Technology
> 60 Musk Ave
> Kelvin Grove QLD 4059 Australia
> +61 7 3138 6443
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> On 28 Jun 2014, at 1:44 am, "Josh Vermaas" <> wrote:
> Hi Tristan,
> I think the string in the file render controls dialog gets passed directly
> to the shell to be executed (at the very least, the text in that dialog box
> never gets passed through a Tcl interpreter that I can see), so it dutifully
> tried to execute tachyon (with passed parameter -res [expr 879. I'm not sure
> why it didn't die when the first argument wasn't an integer) on the list of
> files * 5] [expr 886 * 5]. The wildcards * are what got you into trouble,
> since it will try to render everything in the current directory (twice no
> less, since it appears in the argument list twice).
> What I tend to do is save the tachyon file and then run the renderer
> externally if I want a crazy-big image. (render command = "echo hello", then
> open a new terminal and run tachyon with all the options I want on the
> created data file)
> Good luck!
> -Josh Vermaas
> On 6/27/14, 12:12 AM, Tristan Croll wrote:
> So this is more of a humorous event than a bug that is going to really hurt
> anybody. In order to render a bigger-than-screen-size image using the File
> Render Controls dialog, I added:
> -res [expr 879 * 5] [expr 886 * 5]
> ... to the Tachyon input line, where 879 and 886 are the window dimensions
> from running
> display get size
> Evidently this doesn’t work, since now Tachyon is busy attempting to render
> all 481 files in the current directory (a couple of dozen of which are
> actual Tachyon files), and I can’t kill it without killing my VMD instance.
> It’s nearly done, thankfully...
> Anyway, after all that, I think a really nice feature to add to this dialog
> would be a “screen size multiplier” box or drop-down menu, to make it easier
> to render very large images without the need to know the specific syntax for
> each renderer.
> Cheers,
> Tristan

Dr. Axel Kohlmeyer
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.