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| The image at the top of this page started as the USGS "new" SDTS Ticaboo Mesa 30m DEM. A subset was output as a RIB mesh file from PullSDTS 2.0 beta 3a. It shows part of a west-east cross-section of the eastern slope of Mt. Ellsworth just above Lake Powell in the canyon lands of southeastern Utah. The RIB file was rendered with BMRT rendrib and viewed as lines in rgl, and these two images were blended in Photoshop 5.0 to obtain this image. |
By Bill Allen
Synopsis: If you have a RenderMan renderer available to you, please download the zipped meshes linked below and let me know whether you can successfully render 30mFull_ren.rib and 30mN+S_ren.rib on your machine.
The PullSDTS 2.0 beta 3 is being developed with new 3D viewing and RIB mesh export features, but a problem has been encountered. Posted here you will find RenderMan .rib files that render OK, and others that benignly crash Blue Moon Rendering Tools' rendrib on my machine. If you have BMRT or other RenderMan renderers or previewers, it would be helpful to learn what experience is found with these same files on other machines under a variety of operating systems and RAM limits. (BMRT is available free for non-commercial use and is likely to become the primary 3D viewing/rendering engine for most PullSDTS users beginning with the coming beta 3 release, though other RIB renderers are available and may work just as well [*].)
When loading the terrain mesh as a RenderMan PointsPolygons primitive into BMRT rendrib on a 650MHz 192Mb Windows ME machine, I have encountered a boundary somewhere between 256,852 and 258,108 polygons. The difference is a successful and reasonably fast render, and Windows posting a generic error message while rendrib disappears with little hint about why. The difference is also between being able to render a complete 30m DEM or not. No similar problem has been encountered yet with rgl, BMRT's OpenGL RIB previewer.
This crashing seems to occur during rendrib's "Building secondary hierarchy" phase after loading the full DEM's mesh as either one object or as two halves.
While there can be, and eventually will be, both lossy and non-destructive reduction of the polygon count in PullSDTS's 3D file output, any actual ceiling on the number of polygons rendrib can handle will be a crucial factor in moving on to rendering denser 10m DEMs.
As usual here, testing is with the USGS "new" SDTS 30m DEM for Ticaboo Mesa between Bullfrog and Hanksville, Utah, on the northwestern shore of Lake Powell. The meshes are all contained in RIB "entity" files, which cannot be viewed directly. For rendering and viewing, there are associated _vu, _ren, and _anim.rib files that import the entity file(s). The difference between _vu and _ren files is...
> the _vu files use less intense light settings, and...
> the _ren files include a lake surface blue polygon.
Files without an _ext.rib name extension are entity files without a light or camera, thus not viewable or renderable by itself.
If you are new to RenderMan, drop some of these human-readable ASCII files into a text editor and take a look. Don't be afraid to make small incremental changes to observe how RIB commands work. (More about RIB files.)
Some RenderMan-compliant renderers: From Larry Gritz and Exluna there is BMRT (free for non-commercial use on Linux/Intel, Windows, Irix, and others) and Entropy ($2,000 for Linux/Intel, Windows NT/2000, and Irix). From J. Scott Iverson and SiTex Graphics there is Siren (free for MS-DOS) and AIR ($300 for Windows). There is also 3Delight (currently free for Windows, Irix, OSX, and Linux i686/PPC ), Dot C RenderDotC (for Linux, Windows, and Irix, pricing varies), Pixar PhotoRealistic RenderMan (part of the RenderMan Toolkit, $5,000, for Linux/Intel, WinNT4.4, Irix, and Solaris), and Advanced Rendering Technology hardware-based renderers (PURE PCI card for WinNT/2000, $3,699, and the standalone RenderDrive, starting around $15,000). Pixar also once published RenderMan for Windows that came with MacroModel for Win3.1, and some long-time 3D artists might still have that on a shelf somewhere.
RenderMan on Mac? Lucky you if you have the old Pixar MacRenderMan. It came with 68K programs such as MacroModel and Pixel Putty, and there was briefly a PPC version. The only modern Mac solutions now or rumored are for OSX.
Test reports:
All tests so far reported (thanks!) have been with BMRT 2.6 rendrib.
> Rob Lowrie reports: All of the files work just fine under [Red Hat Linux 7.1] on my 512Mb RAM Thinkpad. 'rendrib 30mFull_ren.rib' takes about 80Mb of memory to run.
> Petr Sorfa reports that renrib ran 30mFull_ren.rib "with no problems" on a 192Mb Celeron system running his own "home grown" Linux distribution. Average memory use was 79Mb. Note that the system was run using libsafe that checks for stack overflows.
> Cecilia Ziemer reports stack overflow when trying to render 30mFull_ren.rib with BMRT rendrib on a 64Mb Pentium Pro running WinNT4 Service Pack 3, crashing before reaching the "Building secondary hierarchy" stage.
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Some Pieces - 30manim.zip - 73.6Kb download, 415Kb unzipped > RIBview is a small Python script that's handy as a simple GUI interface to the command-line BMRT rendrib and rgl. It has a support page here. > 30mN+S.rib, _vu.rib & _ren.rib files import the DEM as northern and southern halves, 30mNorth.rib and 30mSouth.rib, which are in two other .zip files below. Trying to render these two files together crashes rendrib on my machine, thus the view at right is from rgl. The point of splitting the DEM in two is to explore whether the rendrib limit is with individual objects or with all-up scene totals for points and polygons. 169,856 points & 924,387 vertices - 249,745 triangles & 43,788 quads - 293,533 total polygons 
> 30mAnim.rib & _anim.rib are also enclosed, a 2,400m-square subset from the DEM's southeastern corner with the camera rotating 90 degrees over 90 frames. It's fun to watch in realtime viewed as lines, but very slow to render. Unlike the other meshes posted here, 30mAnim.rib has vertex coloring to obtain the blue lake surface and some variation in sandstone color. (32,384 vertices & 9,951 polygons)
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Full DEM as RIB Mesh This is the complete mesh from the DEM data, a file that is crashing BMRT's rendrib on my machine, a Sony Vaio laptop with 192Mb RAM and WinME. 169,856 points & 926,311 vertices 250,201 triangles & 43,927 quads total polygons: 294,128 The image at right is from rgl. 30mfull.zip - 1.87Mb download, 9.65Mb unzipped |
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Northern & Southern DEM HalvesAs exact halves of the DEM, these come with their own _vu.rib and _ren.rib files, and they also can be viewed together, and maybe rendered together, with the above 30mN+S_vu.rib and _ren.rib files. Trying to render them together on my machine crashes rendrib, so the image at right is a composite of the two halves rendered separately in rendrib. > northern half - 30mnorth.zip - 963Kb download - decompresses to 4.68Mb 84,826 points & 475,709 vertices - 138,795 triangles & 14,831 quads - 153,626 total polygons > southern half - 30msouth.zip - 940Kb download - decompresses to 4.42Mb 85,030 points & 448,678 vertices - 110,950 triangles & 28,957 quads - 139,907 total polygons |
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Advisory: This page's URL will remain, but its current contents are very temporary and subject to change at any time, and the linked .zip files may be changed or removed at any time.
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