Inc/Dec Soft Selection Falloff with WMB

I want to set the increase and decrease soft selection (falloff) to a combination of a hotkey and mouse wheel scrolling. But as it seems, that's not an option in the tool customization window (yet).

And btw, would it be possible to inc/dec the reach of the soft selection (what is now called falloff, I believe) and the falloff of the curve via hotkey (preferably WMB-able)? Although I find the curve editor a bit strange. It can go into negative space. I would imagine it more like a normal distribution (with cut-offs of course), where I can set the curtosis (thus the falloff) via a hotkey/WMB and the reach/spread separately from one another, whereas the normal distribution spans the whole selection.

You can set up a streamline tool and bind these two commands to its WBM up/down events.
Selection Tools > Increase Soft Selection.
Selection Tools > Decrease Soft Selection.

But you don't have to do that because some of the basic streamline tools have the built-in ability to allow you to adjust soft selection through WMB. For example, tweak, normal move, polygon normal move...
Once the streamline tool contains one of these basic tools is activated, move your cursor over the mesh, a cage will appear, now you just scroll WMB. Provided you haven't assigned its WMB events to any thing.

You can set up a streamline tool and bind these two commands to its WBM up/down events.

That's one good example for why I think the hotkey setup is overcomplicated.
While it should work for increasing and decreasing the range/reach/spread/fallout or whatever you'd like to call it, what about the curtosis of the curve? I think it's worthwhile, because I wouldn't be fiddling around in the strange and tiny curve editor anymore. I could easily scroll from a peak to a plateau, effectively controlling how strong the pull on the neighboring vertices is.

You can set up a streamline tool and bind these two commands to its WBM up/down events.

That's one good example for why I think the hotkey setup is overcomplicated.

Do you mean you just set a hotkey then automatically wmb-up for increase, wmb-down for decrease?
What if you want to have more functions with one hotkey rather than only wmb functions? Or what if you wnat it like that, wmb-up for decrease, wmb-down for increase?

While it should work for increasing and decreasing the range/reach/spread/fallout or whatever you'd like to call it, what about the curtosis of the curve? I think it's worthwhile, because I wouldn't be fiddling around in the strange and tiny curve editor anymore. I could easily scroll from a peak to a plateau, effectively controlling how strong the pull on the neighboring vertices is.

I am not sure what you mean. The shape of the falloff curve is controlled by three elements, x/y/angle. How do you control this in Maya or other app?

for reference to maya you can only control the fall off size via a holding a key down and dragging mouse like nvil, the curve is set in the current tools properties pane. though maya does have a more advanced curve editor for soft selection, which can have multiple tangents and has several presets for different patterns.

Do you mean you just set a hotkey then automatically wmb-up for increase, wmb-down for decrease?

No. I was referring to the fact, that these 2 actions are already in the tool customization, but for some reason I have to open yet another preference window to first setup a tool to which I then assign these 2 actions to WMB up and down, and assign an additional hotkey, so the tool gets activated. To me that sounds more complicated than saying "open the hotkey setup, assign WMB-up to action1 and WMB-down to action2 or any other hotkey combination if you like." For grow/shrink selection this just works fine, why not for these actions? But that's another discussion, not exactly related to the topic.
But I did setup the tools the way you suggested and now I, too, get this nice visualization of the falloff radius.

I wasn't referring to any app in particular, but had a look at Maya, Silo and Blender. In Blender I wasn't able to find anything that remotely resembled soft selection. As Passerby already showed, the graph editor in maya is more appealing, but not perfect (can't edit tangents) and I wouldn't know how to control the shape of the curve via hotkeys (without scripting). In Silo there's no curve editor for softselection at all, but there's also a differentiation between the falloff radius and the falloff exponent. In the picture below you can see that. I just changed the falloff exponent, the radius stayed the same. Left to rght: 0 (obviuously buggy, because the result should be more of a plateau), 1 (bell-shaped), 2 (peak/spike).

The shape of the falloff curve is controlled by three elements, x/y/angle.

What I was asking for, was a way to control this with a hotkey, preferably WMB compatible. The simplest way I could think of, to change the curvature with a single attribute, is the kurtosis. Here's an example:

For the purpose of soft selection, the curves would have the same mode (as in statistics, or call it height/amplitude), so they fit into another. This is just an example.

With the curve editor as it is in Nvil, I have a hard time getting to the curve shape I want to and can't control it via hotkeys.

I was again thinking about how one could control the shape of a curve more easily and with support of shortcuts. To control the kurtosis of a curve, one way would be to control the horizontal length of the tangent on the tip of the curve. The range would be between 0-1, relative to the overall width of the cruve.
Another addition that would be necessary though, is whether the lower end of the curve has a tangent of its own or not (length of the lower tangent either 1 or 0). So a linear falloff would be an upper tangent with length = 0 and as well as the lower tangent being 0. In the picture below are examples of the curves you could get.
This approach won't let you make crazy curves, but maybe there's a way to do that, too, if it's preferred. For example by adding another CV between start and end.

I can't use curtosis curves due to restrictions on curves that can be used. The new 'Cycle Up/Down Preset Soft Selection Shape' should be closed enough to what you want.

Your solution definitely works for me, so I'm happy!
I'm almost sorry for bringing this up, because it seems like I won't stop asking for more, but what would also be nice is to have a visual representation of the curve-shape's influence on the mesh, just like it is depicted in the maya screenshot. So the vertices that get influenced the most, would have another color, than those affected less. As a result, I won't have to keep the soft selection window open at all times to see what my curve looks like, since I can infer it from the color gradient.

The vertex color is affected by the influence already. But I think color can't give you a good precise jugement. You can can use a streamline tweak tool(including the 'Brush Move' tool) for this purpose. Activate the tweak tool, once you have dragged out some mesh, scroll WMB for fallout, Space + WMB for shape cycling. The effect can be seen in real time on the mesh. This way you can absolutely get your expected result. Once you get expected result, you can Right click to cancel the action if you like.

The vertex color is affected by the influence already.

Oh, I'm sorry, I didn't saw that, because somehow, both my selection color and "soft color1" were set to yellow. I changed that. But I wondered what "soft color 2" was for? It didn't seem to have an effect of soft selection visualisation.

The effect can be seen in real time on the mesh.

That's awesome. I didn't realized it can be used this way. I have nothing else to add. Well done.

'Soft Color 2' is for negative influence.