If you double click on MD slider, you can change the range but not the values - would be nice to have… Of have an input to add the values/range to the MDSlider. Getting .5, .5 is almost patience trying to the point (when it updates slowly your model and values jump) so you delete the MD slider and add a fresh one.
The second question
How do you activate the 3D GUI? I couldn’t find help on this. Nothing about this or other “parameter” components in the reference.
You’re right though, a reset option would probably be a great addition.
That’s probably a feature that hasn’t been properly implemented yet? The usefulness is even debatable, since I image moving a point within a three-dimensional cube, just to construct three numerical values, would even be more cumbersome, than reverting back to 0.5 ; 0.5 with the current MD Slider component.
The numerical values that you see in the MD Slider (i.e. 0.5 ; 0.52) are probably rounded to two decimal places. In reality, these uv- or xy-values are probably floats or doubles with higher decimal precision that get rounded for ease of use and a nicer, more concise UI representation.
This entails that when you move the slider to some position and then back to 0.5 ; 0.5, you might not really be at precisely 0.5 ; 0.5. It’s a small trade-off though. Just imagine trying to manually position the slider back to 0.500000... ; 0.500000....