Hi there.
In the past we were able to bake displacement with Blender Internal, but now it seems there is no option with Cycles, how can we bake the displacement from a hi-res object to a low res object? (for example a hi result sculpture and low res with a proper mesh and UV’s)
Cheers!
That only works for multires. BI had raytraced displacement baking.
You can use shrinkwrap with a highly subdivided multires object and get at the end result that way, but it’s roundabout nonsense. Also the subdivision required to capture all the detail for a 4k texture is not pleasant to work with.
A native displacement baking solution is sorely lacking.
It should be taken care of on highest priority. I am surprised such a crucial baking option is not in 2.8!
We need Blender Internals Rasterization Baking…
It was good at baking normals and such from Intersecting meshes without any issues at all
Meanwhile, with Raytracing I have endless issues with crevices like between fingers and other close areas…
Also, we need an option to disable Rays from hitting Backfaces, for example, I tried to bake a small patch of a model onto another only to realize its shooting rays right through the mesh and baking on the other side…
TBH we don’t need Blender Internal anything 
I mean, Blender Internal was old, full of old code and old techniques, what wee need in any case is Eeevee supporting displacement and being able to bake properly, but with new code/techniques, and I think that’s coming
I hope that Eevee could at least support some Rasterization baking like Blender Internal did
And that’s all, just Rasterization baking as an alternative to Ray baking.
Because with Cycles I have to rely on Multiresolution modifier to avoid baking from humanoid model to humanoid remeshed model Or I’ll run into intersecting issues that Rasterization baking never had issues with 
Cycles is a rasterizer in the end, so if does something it would be rasterized
Then what’s with the Displacement stuff being an issue?
I forget, did Blender Internal only do Displacement baking?
I just realized this - is Blender in 2.83 still not able to bake height maps?
Is this on the roadmap somewhere, because this is a really essential thing missing in internal, right here.
I’ve been using 2.79 to bake simple displacement things lol
This is still a thing. And what’s worse - 2.79 now crashes with 2.91 files 
Now I’ll have to redo a chunk of work into Z-renders. Which overall is not a realistic work-flow for anything but the simplest cases in once a month hick-ups.
Also it can’t be replaced with Multires baking, as the usual case is to seamlessly (without hard edges) add details that are incompatible with mesh topology (details in the smoothly curved subdiv surfaces etc.).
So far still only via multires modifier it seems. Or maybe with a plugin, like grabDoc (haven’t tried it myself yet, though).
Otherwise baking still best done via Marmoset or Substance bake tools. The latter being the goldstandard in flexibility, speed and quality for me. I would love if Blender internal came anywhere close to Substance, but right now I wouldn’t hold my breath for it.
