@Rafael I think the latest comments from @Baardaap and @Bobo_The_Imp already answer everything.
If you’re still skeptical about this just upload your Blender 3.6, 4.0 or 4.0.1 file here and I’ll upload a version of it where the shader outputs are identical when opened in 4.1.
It’s important that the .blend file you upload was saved in a Blender version prior to 4.1 or else it won’t work.
Thats the thing, dont use the same file and import, build the same thing using noise from the ground up in 4.1
You cant get this result in 4.1
You values game this image, i had to tweak a bit more to get close.
Make a new file insert the same value as you did.
Please everyone, keep this task on topic. It’s a developer forum, for user support there are various other forums and places on the internet.
As mentioned before, the exact same results are possible. But since this seems a bit unclear, enhancements to the manual and release notes can be made I think.
Thomas, with respect - when there’s such a significant change in something like this, a user posting “this change doesn’t work correctly” in a thread that was specifically created to discuss the upcoming change - does not appear off-topic.
I’ll agree that the issue appears to be resolved now, but the question was valid.
The release notes have been updated to feature instructions on how to get the Noise Texture to have same output as Musgrave: Reference/Release Notes/4.1/Rendering - Blender Developer Wiki
Hope this helps.
Its a 4.1 file, new file, im inputing the values i got from importing a 3.6 file into 4.1.
I never get the visual if i go direct to the new noise.
I could make the last example work some days ago.
When i say i cant get the same result going directly with a fresh file in 4.1.
If i import it works right away.
For the regular mentally retarde user like me, it does not work. =]
Cant you put it back, as he asks again knowingly that blender devs once they go in a way they won’t go back…
And I can replicate conversion result by adding Map Range node.
Looks like hidden leveling adjustments happening in converted node.
Test on a new build and make sure the Normalize checkbox is not active.
I bet that’s the difference, as @LazyDodo pointed out above
That is probably the reason, Jacques committed the fix yesterday, but windows buildbot is still outdated, so I cannot confirm.
I tickled the bots, there should be a new one up now.
Thank you, new builds have Normalized checkbox accessible, and turning it off makes 4.1 Noise texture behave identical to 4.0 Musgrave version.
@Rafael There was an oversight when renaming the Normalize property, which made it inaccessible. As mentioned by @Mikhail_Rachinskiy it’s already fixed by now.
Sorry for the inconveniences caused.
As i said i were using for displacement as well. Found that the 17th build still have the musgrave.
These green thing it was the last thing i did, could make a garden in no time. And magically i would have just to scale in the z to get the origami.
Sun lamp, red, the nodes are up there, finally i found the build that still has… now i will have to backup 300gb of blender files so i have them open in this specific build so i wont mess all.
This thing about noise is because it is colored and it doesnt give the contrast, dark spot right away.
A whole year of 4.1 and the only thing in the rendering is deleting the musgrave, making it invisible and to subtract -1 of whatever…
If at least you had dropdown menu exposing musgrave as a option and would act just like it, making it invisible is just… one year of work it seems.
Keeping on with the cube posted. See this all nice effect. This is not traditional 3d and don’t think any blender dev do anything like this, and thats always the super hard case to make it understandable to the devs
Couldnt post the video, the link to the video on my twitter.
If opening a file gives a different end-result in 4.1 than 4.0 for the converted texture that’s a bug you should report.
The result of the Noise Texture should be exactly the same as the result of the Musgrave texture in previous versions (with the converted inputs).
Musgrave in 4.1 could be a nodegroup consisting of a noise texture and some math nodes, though I think it was decided not to bundle that by default it should be easy enough to add yourself. You could copy it from a converted 4.0 file.
edit: These kind of changes are not done ‘just because’ to spite artists. Code needs to be maintained as well , not just created. Having the same node implemented twice with different default settings is just a waste of maintenance costs. Especially shader nodes which need multiple implementations (cycles vs eevee,gpu vs cpu) .
It would be helpful for the documentation to actually show the math nodes as an image, instead of merely the equation. A lot of artists aren’t mathematicians, and will not immediately know how to build a node chain of Roughness = power(Lacunarity, -Dimension).
And certainly, there will be a point that “download 4.0, build the shader there, and import it” will be an odd bit of official advice. 
I don’t disagree. Imo it would be wise to just distribute a Musgrave nodegroup by default because I foresee an endless stream of questions in #support. However, I think others disagree because of the simpicity of said nodegroup.
