Index
DMX512
DMX 512 is a method to control entertainment devices. It works by sending 512 channels either over RS485 or over Ethernet network via protocols like ArtNet or sACN. When DMX is sent over Ethernet, each group of 512 channels is called a Universe. You can read more about DMX512 on the web.
Each controlled device requires certain number of DMX channels - these numbers are given by the manufacturer of the device, each channel then typically controls one feature of the device, for example dimmer, horizontal panoramic movement (pan) or vertical tilting movement (tilt) and so on. Each channel can carry 8bits of information, that is a value between 0-255. Sometimes, more precise control is needed, in that case multiple (typically two) channels are used to form 16bits - being able to carry value between 0-65535.
In order to control or visualize devices a description of what device features are mapped to what DMX channels is needed, this is where GDTF comes in.
DMX Addressing
As the DMX512 contains 512 channels, it can for example control up to 512 Dimmers. Each Dimmer will have it’s own address (1-511). If the device is for example LED fixture with RGB channels (3 channels) one can control 512/3 = 170 RGB fixtures. Each fixture will be addressed in such a way that it’s channels are not overlapping with other fixtures, so for example: 1, 4, 7… More complex devices require more channels. If the dimmer or RGB control requires 16bit channels, then 2 channels per each function (dimmer, red, green, blue) are needed.
Each device needs a DMX address, this is the “starting” DMX channel of the DMX signal. If more universes of DMX are used, a Universe number is also required. If more devices are given the same DMX address, they will react together and cannot be controlled separately. This is sometimes wanted in order to save DMX addresses on the DMX console.
DMX Universes and DMX Protocols in BlenderDMX
A Universe is a group of 512 DMX channels. BlenderDMX supports the following protocols to control the devices:
- BlenderDMX contains a simple Programmer for Dimmer, Pan, Tilt, Colors, Zoom and Strobe, universe counting starts from 0.
- sACN protocol counts universes from 1, thus the first universe is 1, second 2…
- Art-Net protocol counts universes from 0, thus the first universe is 0, second 1…
BlenderDMX DMX driver for Blender
The BlenderDMX addon provides a custom DMX driver for Blender, allowing to use received DMX values and use them as input for any Blender property. To utilize this feature, #bdmx(universe,channels(s)) keyword can be used, universe is desired universe, channel is an address and it can either be a single one for 8 bit value or multiple, for 16, 24, 32… bit values.
So to receive 8bit value from universe 1, address 20, this is the syntax: #bdmx(1, 20):
To receive a 16bit value from universe 2, address 30 and 31, this is the syntax: #bdmx(2, 30, 31).
The channels can be in any order, depending on how the console is sending it, for example #bdmx(1, 21, 20):
In order to see 3D objects being animated through this driver, the animation player must be in the “Play animation” state: