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Blender 2.75 Testbuild Now Available


The Blender Foundation has released the first testbuild of Blender 2.75 and is asking everyone to help test it.

We are finishing work on a massive 2.75 release. A first testbuild is available now! Please help testing it and report issues to the bug tracker.

Among new features are AMD OpenCL rendering and stereo/multiview support!

About the Author

Bart Veldhuizen

I have a LONG history with Blender - I wrote some of the earliest Blender tutorials, worked for Not a Number and helped run the crowdfunding campaign that open sourced Blender (the first one on the internet!). I founded BlenderNation in 2006 and have been editing it every single day since then ;-) I also run the Blender Artists forum and I'm Head of Community at Sketchfab.


  1. Wow, i didn't follow blender development very much the last weeks and so i'm quite surprised light portals made it in so fast. Will be a great improvement for my interior renderings :) downloading & testing now - so excited :D

  2. If i'm building from master, do i get the patched OpenCL cycles, even tough version number is still 2.74.5? Because i ran a build on linux, and when trying to render on gpu it spits out "OpenCL build failed: errors in console".

    It was already doing this in a previous build, but it would work if i first rendered the default cube scene. Now it always fails.

    • Ok, i reply to myself to say that i tried the "official" test build and it works, so it's definitely a problem of my build, tough i'm uncapable of identifying it.
      If anyone can help me, this is the output of my console:
      Compiling OpenCL kernel ...
      OpenCL kernel build output:
      "/tmp/", line 62050: warning: kernel with local addrSpace
      variables cannot be called by other kernels or functions
      Error compiling program for kernel_ocl_path_trace_scene_intersect.
      Frontend phase failed compilation.
      Error: Creating kernel kernel_ocl_path_trace_scene_intersect failed!
      OpenCL build failed: errors in console
      Faled to compile scene_intersect
      Error: OpenCL build failed: errors in console
      I used the tilde (~) to mark empty line, because wordpress would remove them otherwise.
      Also, i build with these options:
      make full -j8 BUILD_CMAKE_ARGS=" -D OPENCOLORIO_ROOT_DIR=/opt/lib/ocio -D OPENEXR_ROOT_DIR=/opt/lib/openexr -D OPENIMAGEIO_ROOT_DIR=/opt/lib/oiio -D WITH_CYCLES_OSL=ON -D WITH_LLVM=ON -D LLVM_VERSION=3.4 -D CYCLES_OSL=/opt/lib/osl -D WITH_OPENCOLLADA=ON -D WITH_CODEC_FFMPEG=ON -D FFMPEG_LIBRARIES='avformat;avcodec;avutil;avdevice;swscale;rt;theoradec;theoraenc;theora;vorbis;vorbisfile;vorbisenc;ogg;xvidcore;vpx;mp3lame;x264;openjpeg' -D FFMPEG=/opt/lib/ffmpeg -D WITH_FFTW3=ON -D WITH_MOD_OCEANSIM=ON -D LLVM_CONFIG=/usr/bin/llvm-config-3.4"
      Ok, sorry for the lengthy post and thanks to anyone who tries to help :P

      • > .. and it works..

        How did you set it to render using openCL?
        When I look in User preferences -> system -> compute device
        I only see CPU listed in the menu.

        • Well... i didn't have to set anything, i just ran the executable. I'm on linux, i don't know if this can be the reason. On previous releases tough i had to run it with this command: "CYCLES_OPENCL_TEST=true ./blender"
          And... i ran another build. This time, i added to my cmake configuration all the settings from blender_full.cmake (except game engine and player) and opencl kernel compiles fine now.
          I noticed another problem, which showed up both on the official test build and on my local build, but never happened on 2.74: sometimes, while rendering in the viewport is turned on, it causes the PC to hang up at random times (sometimes even before starting to render, sometimes after some samples, sometimes it just works ok), forcing me to reboot the system.
          This happens both with GPU and CPU rendering, and it's actually more frequent on CPU.

          Does this happen to anyone else? Should i file a bug report (or someone did it)?

        • Not yet... do you meet this problem with cpu rendering too?

          EDIT: when i have these lockups, i'm often just unable to interact with blender, and i'm totally unable to close the window (it stays open even tough there's no process for blender in the system monitor), but my pc is still responsive and the cpu stops being busy with rendering (ie: it goes idle). Sometimes the whole system locks up and i can only force a reboot.
          As i said, it happens both on CPU and GPU when enabling rendering in the viewport.

  3. properties panel (+) on the right top does not open...i cannot test anything...this is not a testbuild, but a beta version...

    • when I tried to open the properties panel, blender stopped responding and crashed. I also downloaded both regular and gooseberry versions from builder.blender and they have the same problem.

  4. The portal lights are a fantastic addition. Seriously cutting down noise in interior renders. Well done guys.

    • They are intended for specific use cases. If you are using them in that use case, then report a bug, if not, look on the BlenderArt thread about this feature.

  5. Brian Lockett on

    To everyone who's contributed, from the bigger new features to the smallest bug fix, thank you kindly.

    You guys take on a lot of workload, challenge, priorities, and criticism, but you're relentless and passionate about what you do. Thanks.

  6. James Jackaman on

    Blender 2.75 test build not recognising my ATI Radeon HD 5670 for GPU rendering, I guess this is one that will not be supported (not new enough?)

    • SheikYerbouti on

      Pretty sure I read that anything below the HD7xxx series wouldn't be supported, and probably wouldn't work. You could try using different drivers and such but I'd guess it won't work.

  7. Tried on windows 8.1 using HD6870 couldn't get it to run(couldn't build the kernel)
    Tried on the same computer with OS X and it didn't even recognize the GPU
    My scene was a plane with a box on it and another plane as light source

    • SheikYerbouti on

      See my reply to James Jackaman. Pretty sure it applies to you as well.

      It could be something like video memory too. There may be a minimum amount necessary to build the kernel. I'm running a 3GB card and don't have a problem with that, but I have had some test builds lock up at various stages of building/rendering/etc. when using high poly meshes.

        • SheikYerbouti on

          Yeah, sorry I wasn't clear. I don't think the scene matters where your problem is occurring. Building the kernel happens the first time you use GPU for rendering (I think it even says that when it's building). If it doesn't build, your scene doesn't even start to build/render. It's very likely your card just won't work. (think it has to do with the graphics card architecture of cards after the HD7xxx series)
          The comment about memory was just a random thought. I know memory was an issue when trying to get it working before the split kernel patch, but I think that was a compiling issue. Might be the same thing, different terminology. Anyway, I should have left that comment out instead of displaying my ignorance.

  8. After testing Blender 2.75 with my graphic card AMD R7 265, my Blender 2.74 was locked after working on it a little project, some time after, appears a bluescreen on my SO Win 8.1 64-bits with the error in atikmdag.sys.

    • SheikYerbouti on

      I've recently had a similar issue crop up. I was getting seemingly random BSOD's, and the crash dump would usually point to my graphics card driver or CPU. I started figuring out it was (more than likely) Zbrush 64-bit that was causing it. I think there must be a bug that causes the CPU to throw an unrecoverable error. Most of the errors were vague, but a few pointed to an overheating issue. I monitor my temps pretty regularly, and was pretty sure that wasn't the problem. When sculpting in Zbrush, I rarely notice any 'warming up' of the CPU at all. I stopped using the 64 bit version of Zbrush, and haven't seen the crash since.

      I also had a crash with a testbuild, while rendering a relatively simple scene with about 100 samples. That BSOD had me convinced it was a heat issue, and is the main reason I started monitoring my system temps.

      So I said all that to say this. I have no clue about your situation nor mine. When my crashes occurred, I was always watching a movie on my second monitor, or some sort of video using flash player. For a while, I wondered if VLC or flash running while i was using Zbrush and/or Blender was causing the problem. The crash in blender was rendering using CPU, but it was the same error as yours. I disabled hardware acceleration in flash player for a while, and it happened again, but have re-enabled it recently and no crashes.

      I've tried to pinpoint when the problem started. I didn't have this specific problem before getting my SSD, and doing a fresh install of windows, although a few versions of Blender would cause a BSOD when just rotating the view in the viewport. That went away with one of the updates. I also recently installed the beta driver for my graphics card. I'm still not certain it doesn't have some issues. The really odd thing is, the one time my PC has NEVER crashed, is while gaming, for hours on end. Every one of my BSOD's has been while using blender and/or zbrush.

      So again, sorry to type so much and offer so little help, but I do have a few tips if you wanna troubleshoot it, although you may end up like me and still not figure it out.
      There's a program called 'whocrashed' that will analyze your crash dump files. It can (sometimes) give you some extra details. There are also forums where people will dig into the files and offer advice.
      You might also wanna look through the system error logs to see if anything jumps out at you. A service could have failed, causing instability, which may or may not be blender related.
      If you are running a beta driver (I'm not familiar with win8.1) you may wanna roll it back and see if it still happens. If you're not using a beta driver, it wouldn't hurt to try it out for testing purposes.

      i did a quick google search for 'bsod atikmdag.sys windows 8.1' and saw quite a few people with that problem. It could be something solve-able, but I'd guess it's just common for that to be the file that windows thinks caused the crash.

      Final thought....If this only happens with blender, it's probably a blender bug. I'm not sure if you can get some equivalent of crash log files from blender (please someone let me know if you can) but if it's reproducible, a bug report may be the only solution. With opencl for amd cards being kind of new, I'd assume that there may be bugs with it for a little while.

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