# Is netrender only useful for multiple frames?

Trying to speed-up render times on a large single-frame Cycles image by using netrender and a spare machine. The spare is running (in separate terminals) a master and a slave, and the main computer is running a client and another slave.

Pressing F12 from the client works to render the image, however only the slave on the client machine is used. Killing that slave will then cause the slave on the spare to be used. It does not appear possible to have them work in concert. Is it correct to conclude that netrender only divvies frames to slaves, not tiles?

AFAIK, it does not (yet):

From the wiki:

Todo:
Dispatch single frame as tiles

however, another fairly simple way to do this is to render relativity low samples on each machine with different seeds, then combine the images afterwards. (see this post for more info)

• I tried the seed idea last night, doing one render on my very underpowered home laptop and anther with a different seed on the remote work server, and just by mixing two layers in GIMP with the top one at 50% transparency, i saw dramatic results. Thank you gandalf3 for the idea. – Plenus Franckly Jul 29 '13 at 13:19
• +1 for mentioning the seed technique; that's how Renderfarm.fi does it, AFAIK. – wchargin Aug 12 '13 at 4:16
• type '#frame' in the Seed value to give it a driver to match the current frame - then render the animation to get a set of different seeds. For each computer, render a different frame range with no overlapping. – Greg Zaal Aug 12 '13 at 5:48

You cannot use Network Render to render a single frame out-of-the-box. However, it is possible with some tweaking and post-processing.

First, extend your timeline to however many slaves you are going to use. If different slaves have different hardware configurations, you may want to multiply this by two to render slightly faster.

Then, in the PropertiesRender SettingsSampling, select the Seed field and enter the text #frame. Press Enter. (If you see a message indicating that the driver will not be automatically run, either enable autorun for drivers or reload the file as trusted; don't forget to save.) This will tie the interpolator seed to the current frame.

Then, take the Render Samples value and divide it by the number of frames in your timeline.

You can now perform a network render of your file. When your "video" is finished, you can blend the files together to obtain the final image.