VAE Merge Add

VAE Merge Add is the simplest member of this pack's VAE-merge family, and it's a building block rather than something you'll use standing alone. Two VAEs in, one out, every weight simply summed: vae1[key] + vae2[key]. No ratio, no blend knob, no per-block control - just addition.

What it's actually for

Adding two full VAEs on its own almost never does anything useful - you get a supercharged VAE that usually just produces oversaturated or broken output. Where addition earns its place is as the second half of a delta merge. The pattern:

1. Take a base VAE and a fine-tuned variant of it.
2. Subtract the base from the variant (the pack's VAE Merge Subtract is built for exactly this) to isolate the "delta" - what the fine-tune actually changed.
3. Add that delta back onto a different base with this node.

So the honest use is: you're doing model surgery, and this is the glue that reassembles pieces after Subtract carved them apart. On its own, expect garbage.

Inputs and output

Just the two VAEs - vae1 and vae2. No widgets to fiddle with. Keys that exist only in vae2 get copied into the result untouched; keys only in vae1 stay as they are. One VAE comes out, which you'd wire into VAEDecode or a VAE-save node, because nothing here touches disk - the merge exists only in memory.

The rule that keeps you out of trouble

Same as every VAE merge in this pack: the two inputs must be the same architecture with the same channel count. SDXL's VAE is 4-channel; Flux, Wan, and Qwen are 16-channel. Sum two incompatible autoencoders and you get noise or flat color, not a hybrid - the latents they decode simply don't mean the same thing. If you're not sure what you're working with, the pack's Key Name Inspector node will dump both VAEs' weight key names so you can confirm they match before you merge.

Realistically, you'll reach for VAE Merge Simple (a clean ratio blend) or the block-level merge/scale nodes more often. This one is the arithmetic primitive - keep it in the toolbox, use it deliberately, and don't expect magic.