What is the problem? MacOS has a security feature called Gatekeeper. We noticed that it kept stopping crowdrender from working, period. The reason is that when you download Blender, and then extract Blender's files, it is marked by your operating system as to be put in quarantine. This has now been fixed in the pre-release version of 0.1.2. Installing this version (e-mail us for a copy if you are happy to test it :) ) will fix this issue. What OS versions are affected? As far as we can tell, every version of Sierra is affected, we've tested from 12.1.0 up to 12.1.2. Its possible El Capitan is affected but we did not test this explicitly and we haven't rolled back to check this yet. How can I tell I have this problem? Crowdrender would not connect to other machines. To verify if you have this issue, open blender and then choose the scripting screen layout from the menu at the top of the screen. Then enter the following command: bpy.utils.script_paths() You will see a result similar to below, note the unusual path for blender's script paths: /private/var/folders/h8/*some_long_hexadecimal_number/T/AppTranslocation/*more_long_hexythings*/d/blender.app The blender.app is what you requested to run when you opened blender, so why is it running in some weird folder? Welcome to quarantine, if you see this result (especially the "AppTranslocation" words in the paths) you have just confirmed gatekeeper has quarantined blender. Can it be fixed and if so how? If you are comfortable using terminal and typing some commands, you can permanently un-quarantine blender. Here's how to do it. Open terminal from launchpad>utilities You'll need to cd (command to change directory) to where you unzipped blender. On my machine I put the unzipped blender in my downloads folder. You can see below that I first used the cd command to get to my downloads folder. In the image above, I used the "ls" command to show the files in my downloads folder and I can see that the unzipped blender is there. I then use cd again to enter my blender's folder (and wish that I had renamed it so it didn't have the date and time of extraction). Now I can use the xattr command to see if the OS has marked blender as quarantined. xattr shows the execution attributes for blender.app (that is the icon you click on to launch blender). You can see that it has one attribute: com.apple.quarantine. We can remove this with one command and blender will now run from the location you unzipped it and crowdrender will work! The command to run is xattr -d -r com.apple.quarantine blender.app (see above). This tells the OS to delete (-d) the com.apple.quarantine attribute from blender.app and to do this recursively (-r) throughout the blender package. Now try running blender again. In blender, once again, open the scripting screen by using the drop down menu at the top of the user interface and then type: bpy.utils.script_paths() You should see that blender is now referring to the location where you unzipped it rather than the weird location before we removed the com.apple.quarantine attribute. This means that crowdrender will now (hopefully) work. Note, now you have removed this attribute, it will not come back again for this particular copy of blender, but if you download a new copy of blender and attempt to use it, it most certainly will happen again. At this time, we're not sure if this is an issue with blender or gatekeeper. Either way it doesn't look like placing blender in quarantine is intentional by either of those parties, its likely that no one has realised yet since it really doesn't affect blender, only poor old us!

Scope Currently the crowdrender alpha supports rendering files that only refer to data that is locally available. What does that mean? It means that all the data needed to render your scene needs to be in the blend file you are working on. There is a workaround for those of you who desperately need to render using crowdrender and have references to external files, we'll cover this in detail below. However, for simplicity, crowdrender expects your scene data to be in the blend file you currently have open. You can work with external files in some cases, with texture files for example. You can use the "pack into blend file" option that will save the textures as part of the blend file. Watch your file sizes grow accordingly though. This data will be transferred to your second machine. For files that cannot be packed into the blend file you are wanting to render, you will need to use the workaround below: Workaround Lets go over the basics of what we're doing here before the steps you'll need to carry out, if you are a pro read ahead to the method. Blender is quite nifty in that it will allow you to include a range of external files in your scene that can form part of the final rendered image, textures are one, other blend files with models in them are another (there are a ton of good tutorials out there you should probably watch if you haven't already regarding good structures for projects). The problem is that not all of these files can be packed into the blend file and if you need to keep files external (if you are editing them externally) this is a problem for crowdrender. Our addon (in its alpha version) only transfers the blend file you are working on, not its dependencies (all the files you refer to in your scene). For example, if you have a scene of a room and you have other blend files containing furniture for the room, this is a problem you'll need to solve with the workaround. This workaround assumes you will not be editing your external files and you are ready to do final tweaking and rendering, not remodeling or re-texturing. Methodology For this method to work, you will need to have made sure that you use relative paths for all your external files. The reason for this is that you are about to copy those external files to your second machine. As a result, the paths need to be relative so that on the second machine crowdrender can find them relative to the copy of your blend file it will transfer to that second machine. When you open a project with crowdrender enabled and connect to the second machine, a special folder is generated to hold the blend file and rendered images. This folder is where the external files will need to go. Recommended Project Structure By project we of course refer to your blend file that you wish to render and all of its dependencies, files it needs to render the scene. Here is an example of a good project structure. The scene is a room with some furniture in it. /project_directory/my_room.blend /project_directory/textures/wood.png /project_directory/textures/carpet.png /project_directory/textures/wall_paper.png /project_directory/furniture/chair.blend /project_directory/furniture/table.blend /project_directory/furniture/carpet.blend The blend file that is rendered is my_room.blend and it uses the other files to do this, it needs the models and textures from the other files to render the scene. Please follow this structure and use relative paths for this workaround to be successful. You need the blend file that renders at the root directory of the project. It gets very messy otherwise and makes life hard for you if you have this blend file in a sub-directory of the project directory. Copy your external files to the second machine Back to the workaround. Since crowdrender is only going to transfer my_room.blend to the second machine, how can this work? The second machine won't be able to complete the render... unless you manually transfer the other files. This is where the special directory comes in. If you can find that directory, you can simply copy the files into this directory and then restart crowdrender and connect and you will be able to render. Here's how to do it, step by step. 1. Open blender on both your working machine and second machine, make sure they're connected to the same network. 2. On your working machine, open the file you want to render, enable crowdrender and connect to the second machine. This will of course only transfer the blend file you want to render, its necessary since it ensures that the special directory will be created. 3. On your working machine, in blender, at the top of the UI, set the screen to be "Scripting". 4. In the python console that appears, type the command you see in the image below which is "C.scene.crowd_render.session_uuid" and note the hexadecimal string, this is the name of your special directory for this blend file you want to render. 5. Copy the external files of your project to a USB stick and take them to your second machine. 6. Search for a folder which has the name of the session_uuid you just found in step 4. It should be on a path like "*user_directory*/cr/server/*session_uuid*". 7. Copy the external files here. 8. Restart Blender and crowdrender and then open your project, enable crowdrender and connect to the machine you copied the files to. 9. Render! Vote up external file support After spending what seemed like a very long time writing this workaround, the feature to automatically manage all this for you is definitely getting my vote! We're currently working on a version that will detect and manage your external dependencies so you don't have to worry about them. If you link, append, do simulations or have textures you don't want to pack since you wish to continue editing them, this feature will enable you to use crowdrender concurrently in your workflow, no problems! Read about and vote for this feature here.

Problem or Use Case Currently the scheme used to divide the frame between machines only takes into account the relative power of the computers taking part in the render. This can have the effect of reducing performance when a scene has complexity only in one part of the screen. The image below shows this situation. In this scene, where two computers with similar performance (cores in our case) render this scene, one machine will end up with a much higher workload since it will render most (if not all) of the planet with the othe machine only rendering the background. Proposed Solution Take account of the contents of the scene to ensure a balanced load between all machines on every frame. This will give maximum performance regardless of how the scene is composed.