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# mental ray Release Notes

Version 3.1.3.16

# Distribution Package

This release includes the following programs and documents:

- mental ray 3.1.3.16

- imf_disp 3.1.3: image and flipbook display program

- imf_copy 3.0.2: image conversion program

- mental ray User's Manual and Reference, version 5.2

- mental ray/mental matter Release Notes, Version 3.1.3.16

Note: mental ray 3.1 is compatible with the `shader.h` files provided with mental ray 3.0, and can execute shaders written for mental ray 3.0. This may generate an error message if the declaration files for these shaders specify that they require version 3.0, but the error can be ignored.

mental ray for Linux is tested on RedHat 6.0, 7.0, and 7.2. RedHat 5.x and other older distributions may be unable to run mental ray. RedHat 7.1 has a pthread library problem and should not be used. On SGI machines, mental ray requires IRIX 6.5, but also works on old IRIX 6.2, 6.3, or 6.4 machines provided that the appropriate Posix threads (pthreads) libraries are installed. Future versions will support only IRIX 6.5 or later; 6.2-6.4 are long obsolete and unsupported by SGI.

# Changes in version 3.1.3.16

- Substantially improved efficiency of network rendering. Hosts and threads no longer go idle if there is still work to do.

- Intel Pentium 4 processors with hyperthreading support appear as two virtual processors to the operating system (Linux or Windows NT). However, this doesn't make the processor twice as fast; 15% faster is more likely. For this reason, mental ray no longer pulls a second license for these phantom processors, a hyperthreaded processor now consumes only one.

# Changes in version 3.1.3.15

- Fixed a problem introduced in 3.1.3.14: displacement mapping on merge groups of objects was computed incorrectly, and could abort mental ray in some situations.

# Changes in version 3.1.3.14

- The mi_query shader interface function can now be called with mode `miQ_GEO_DATA` from displacement shaders.

- Fixed confusion of primitves in sorted and segmented shadow mode when casting shadows from hairs. (This was introduced in 3.1.3.13.)

# Changes in version 3.1.3.13

- Hair geometry now works in sorted and segmented shadow modes. These modes are useful for some kinds of volumic effects such as ray marching. Also, fixed a bug that could abort the second frame of animations if there were hair objects and incremental changes.

- Hair geometry now works in sorted and segmented shadow modes. These modes are useful for some kinds of volumic effects such as ray marching. Also, fixed a bug that could abort the second frame of animations if there were hair objects and incremental changes.

- The shader interface function mi_tri_vectors now returns false if applied to hair geometry (which does not involve triangles), instead of returning undefined data.

- Shadow rays that left the scene without hitting any geometry could be incorrectly considered as black, i.e. in shadow. Fixed.

# Changes in version 3.1.3.12

- Library versions of mental ray now work on Windows NT if the stderr stream is unavailable.

- On Macintoshes, the number of CPUs in the system is now determined correctly.

- Improved performance of motion-blurred hair. Also fixed an intersection problem for raytraced shadows.

# Changes in version 3.1.3.11

- Attempts to use finalgather diagnostic mode and photonmap diagnostic mode simultaneously is not correctly rejected. Only one diagnostic mode may be active.

# Changes in version 3.1.3.10

- Allow ``diagnostic finalgather on'' in the options in the scene file.

# Changes in version 3.1.3.8

- Triangles that were exactly coplanar with BSP voxel boundaries could get incorrectly rejected, and disappeared from the rendered image. Fixed.

- Large scenes with very thousands of objects, instances, materials, etc, could cause hash collisions in a job manager table that keeps track of which objects are available for garbage collection when memory runs out. These collisions could keep large numbers of normally flushable objects in memory, leaving garbage collection ineffective and causing mental ray to abort with memory errors eventually. Fixed. This fix has a profound impact on the maximum size of scenes renderable with mental ray.

- User-supplied tessellated geometry will no longer be deleted during postprocessing, leaving them available for the next frame. (This affects only the mental ray integration interface.)

- It is now legal for a lens shader to call mi_sample_light, as documented.

- Implemented additional reading support for custom Lightworks images.

# Changes in version 3.1.3.7

- When rendering with an orthographic camera (`focal infinity`), a numerical inaccuracy could cause visible cracks at the raster axes. Fixed.

- If mi_trace_probe was used in a scene using final gathering, mental ray could crash when rendering was complete while printing ray statistics. Fixed.

# Changes in version 3.1.3.6

- Fixed memory leaks inside begin/end blocks in shader declaration files using Softimage's SPDL syntax.

# Changes in version 3.1.3.5

- The `-echo` command-line option did not echo `exponent 0`. Since the default is 2, not 0, 0 is now echoed.

- Reduced memory requirements for tessellating free-form surfaces with very high subdivision depth settings.

- Trying to read scalars from a color texture is not legal and returned junk data. This case is now detected and handled.

- Light lists can now be obtained with mi_inclusive_lightlist and mi_exclusive_lightlist using varying argument lists.

- Autovolume camera initialization could get confused by visible area light sources. Now all volumes enclosing the camera are detected correctly.

- The minimum size of shadow map rectangles is now 16 pixels, regardless of the `-task_size` command-line option. Very small shadowmap rectangle sizes can cause long startup delays and higher memory use.

# Changes in version 3.1.3.4

- Corrected echo of the number of motion vectors for hair objects.

# Changes in version 3.1.3.3

- Motion transform created by a traversal shader was ignored. Fixed.

- In mi_sample_light, state>light_instance is always set to leaf instance no matter if DAG or leaf instance was passed as an argument.

- Fixed Linux Intel-compiler specific motion BSP atrifacts.

# Changes in version 3.1.3.2

- Fixed self-intersection test in segment shadow mode.

- Improved tessellation parallelization in Inventor mental ray.

# Changes in version 3.1.3.1

- Fixed hair object echo.

- Fixed scene preprocessing if traversal shader returns null motion transform for the camera leaf.

- Fixed mi_inclusive_lights / mi_exclusive_lights when called from init shader.

# Changes in version 3.1.3

- Added a new query type miQ_FUNC_CALLTYPE which returns the type of the shader call of the executing shader.

- Call traversal shader when searching for the camera.

- Avoid unnecessary geometry access when merging object sample limits.

- Assure that tesselated geometry is deleted with source geometry immediately.

- Fixed a crash for incremental non-placeholder objects.

- Fixed a crash in coverage filtering with Lanczos and Mitchell filters.

# Changes in version 3.1.2.11

- Upgraded Linux x86 gcc3 compiler to fix crashes due to an optimizer bug.

# Changes in version 3.1.2.10

- Fixed database tag leak for autoload objects.

- Running mental ray on unsupported Windows versions will no longer result in immediate abort.

# Changes in version 3.1.2.9

- Added read/write support for floating-point IFF images.

- Fixed a crash if a pipe-connected imf_disp was closed early.

- Fixed a crash that rarely occured during hair rendering.

# Changes in version 3.1.2.6

- Fixed a tessellation memory leak.

- Motion blurring now works correctly if the only motion in the scene is caused by a camera motion transformation.

- Added the Z type to the Alias|Wavefront Maya IFF image format.

# Changes in version 3.1.2.5

- Fixed a bogus error message complaining about deleted jobs being done.

- Fixed the shader interface functions mi_inclusive_lightlist and mi_exclusive_lightlist, so that a shader can call them multiple times with different arguments.

- Raytraced shadows from visible lights could cause problems in autovolume mode, because the list of initial volumes at startup was off by one. Fixed.

- The minimum rectangle size in shadowmap mode is now 16 instead of 1. The overhead for one-pixel rectangles was too high, causing very long startup times.

# Changes in version 3.1.2.4

- Set state - > instance for hair intersections.

- During traversal, mental ray tries to keep track of different instance transformations with a transformation `id'. This was not working if instance transformations were handled using a traversal callback and the dag transformations were ID transforms. Fixed.

# Changes in version 3.1.2.3

- Fixed traversal shader problems. Use inheritance function from Option if mi_rc_run is passed a NULL inheritance function pointer.

# Changes in version 3.1.2.2

- Fixed image tile display issue occuring when rapidly aborting and restarting rendering.

- Fixed module removal issue on Windows NT.

- Fixed an issue when rendering with zero shutter value but a motion output buffer being specified.

- Fixed regression with depth buffer rendering.

- Fixed seam problem with nurbs cylinder texturing: Don't attempt seam compensation for surfaces that cannot close up.

# Changes in version 3.1.2.1

- Non-color frame buffers were written to files incorrectly (truncated horizontally to 25%) on 64-bit machines.

- The depth frame buffer got the farthest intersection depth when rays pass through transparent motion blur trails. Now it's the frontmost, which corresponds with the way this is documented for transparency. Since motion blur looks like transparency they should behave the same way.

- Computing the inclusive or exclusive lightlist for the shader instance in the shader instance init function could lead to deadlocks.

- The mi_link_file_remove integration interface function was disregarding the library reference count, and always removed the library even if the count is greater than 1.

# Changes in version 3.1.2

- Fixed a problem with shadow mapping quality at high sampling settings. (The problem was introduced in version 3.1.1.184.)

- Shifted the Woo midpoint of shadow map lookups slightly away from the illuminated surface, to reduce surface acne where the light reaches the surface at a grazing angle. Note: this can slightly shift shadowmapped shadows.

- The Maya IFF file format is now supported for reading.

- mental ray now correctly prints an error message when the scene file tries to put a nonexisting item into an instance.

Copyright Information

mental images Gesellschaft für Computerfilm und Maschinenintelligenz mbH & Co. KG, Berlin.

All rights reserved.

This document contains proprietary and confidential information of mental images GmbH & Co. KG and is protected under copyright law. The contents of this document may not be disclosed to third parties, translated, copied or duplicated in any form, in whole or in part, without the express written permission of mental images GmbH & Co. KG.

The information contained in this document is subject to change without notice. Neither mental images GmbH & Co. KG nor its employees shall be responsible for incidental or consequential damages resulting from the use of this material or liable for technical or editorial omissions made herein.

mental images®, mental ray®, mental matter®, mental ray PhenomenonTM, mental ray PhenomenaTM, PhenomenonTM, PhenomenaTM, Phenomenon CreatorTM, Phenomenon EditorTM, Photon MapTM, mental ray RelayTM Library, RelayTM Library, and Shape-by-ShadingTM are trademarks or, in some countries, registered trademarks of mental images GmbH & Co. KG, Berlin, Germany.

All other product names mentioned in this document may be trademarks or registered trademarks of their respective owners and are hereby acknowledged.