DMX out start channel

I might be missing something here(apologies if I am), but the DMX out CHOP seems to be limited to starting at channel 1 of any given universe.
This has implications in the lighting world that might not be immediately obvious, for example having to setup an artnet merge of TouchDesigner’s data with existing infrastructure that is already addressed.

Hi.
How does this work in practice?
If TouchDesigner were to send slots 50 through 60, does the receiver have to be configured with this information (ie, data begins at slot 50)?
I don’t see anywhere in the DMX512 protocol for example, that lets you specify the starting slot number index.

I was under the impression that common devices such as the Enntec’s only dealt with full 512+1 payloads.

Or Is it just simply DMX Out CHOP should allow sending smaller payloads when presented with less data (example 10 values) ?
Thanks for the clarification,
Rob.

There is a way in the Art-Net spec to send LESS than 512 values (which I’ve never seen used in the lighting industry), but there’s no way in the Art-Net spec to NOT send values starting from DMX channel 1.

According to the Art-Net spec, the correct way to handle merging is for the receiving device to merge packets from different IP addresses to the same universe as either “Highest Takes Precedence” or “Latest Takes Precedence”, or indicate an error.

More info on this shows up on page 48-49 of the Art-Net spec:

[url]https://www.artisticlicence.com/WebSiteMaster/User%20Guides/art-net.pdf[/url]

In TouchDesigner, if you want to start at a higher channel than 1, use a constant CHOP and a join or merge CHOP to add a bunch of 0 values before the values that you want to send.

Every instance of ArtNet I’ve seen in production broadcasts whole universes of data.

As peeet said, if you want to merge two universes of data, you need to take two ethernet lines into a system that can parse them in tandem and perform an HTP-merge.

Merging two universes of ArtNet data using conventional network gear doesn’t work, since all the channels walk all over each other. If you need to accept input from two ArtNet devices on a given network, you usually want to have them broadcasting on their own universes and address the controlled gear to suit.