Several questions regarding curve mode

[Noren]

Hi,

I’m getting more into ZBrush again and encountered a few possible problems concerning curve mode / curve brushes with ZBrush 2020.1.4.

When sculpting on a surface, they work ok when using the mouse, but go crazy when using a pen with activated pressure sensitivity (that works well otherwise in ZBrush).

I can drag the curve out just fine, but when it comes to applying it by dragging on the curve, it throws lot’s of crazy coils/spirals/waves, many of them detaching from the surface as if the curve got a lot longer and needed to account for that (no matter if the start and/or end point are fixed or not). This happens pretty much immediately, so dragging out a shorter distance, even much smaller than with the mouse, doesn’t help.

Activating Liquid does help, but this seems to be a bug related to pressure sensitivity to me. (Anything less than full pressure throws those curves by making the base curve a lot longer than the motion would account for.)
Does anyone else encounter the same?

Generally, the system of manipulation the curve and “applying” it with the same action/motion seems cumbersome to me, to be honest.

Both with mouse and pen the curve is sometimes subtracted from the surface instead of adding to it and I can’t quite pinpoint when that happens.

I can’t seem to find these settings described in the reference guide:

“The amount of bend at the cursor location is defined by the Curve Falloff settings, located at the bottom of the Curve menu. A Curve Falloff which has the point at the top left will produce a rounded curve deformation while a curve falloff which goes to the bottom right of the curve line will produce an angular curve. Bend mode is enabled by default.”

There is a Curve Falloff in Curve Modifiers, but that seems to be for Intensity/Size and doesn’t seem to affect the falloff of the bend.
Has this been deprecated and replaced e. g. with FocalShift?

Then, is there a way to adjust the curves for Intensity and Size separately? E. g. if I want a curve to get wider and flatter towards one end?

Lastly turning on Backtrack in LazyMouse and then deactivating LazyMouse still keeps Backtrack active with Curve Mode

Generally, what is the best method to report bugs? Here in the forum or directly to support? Will moderators log bugs reported in the forums?
Is there some kind of public bug tracker to check if a problem has already been reported besides doing a search in the forums?

[Spyndel]

Hello @Noren

@Noren

When sculpting on a surface, they work ok when using the mouse, but go crazy when using a pen with activated pressure sensitivity (that works well otherwise in ZBrush).

We’ll come back to this if nothing else solves your problem.

---

@Noren

I can drag the curve out just fine, but when it comes to applying it by dragging on the curve, i

You can apply a stroke to a curve by simply clicking on it with a brush that has curve stroke enabled. There is no need to drag on the curve, as this edits the placement of the curve. Again, do not drag on the curve unless you want to edit its placement. Just tap it.

---

@Noren

“The amount of bend at the cursor location is defined by the Curve Falloff settings, located at the bottom of the Curve menu. A Curve Falloff which has the point at the top left will produce a rounded curve deformation while a curve falloff which goes to the bottom right of the curve line will produce an angular curve. Bend mode is enabled by default.”

There is a Curve Falloff in Curve Modifiers, but that seems to be for Intensity/Size and doesn’t seem to affect the falloff of the bend.

This is what you’re looking for. Read the Ctrl-mouseover description.

@Noren

Then, is there a way to adjust the curves for Intensity and Size separately? E. g. if I want a curve to get wider and flatter towards one end?

You can enable both the size and intensity modifiers at the same time, but they’ll both be modified by the same curve. Zbrush is designed for use with a pressure sensitive tablet, and most tapering/variable intensity strokes will be the result of the pressure sensitivity.

@Noren

Lastly turning on Backtrack in LazyMouse and then deactivating LazyMouse still keeps Backtrack active with Curve Mode

Lazy Mouse + Backtrack and Curve stroke mode are two different things, and I don’t believe they are designed to function together.

To see Lazy Mouse +Backtrack in action, use it with a non-curve stroke brush like the standard brush with lazy Mouse active, and backtrack set to whatever stroke type you want (Line, path, etc). It will let you draw out a quick path, then sweep back and forth on it, but this is not the same thing as drawing out a curve. Backtrack and lazy mouse both disable just fine when you switch off LM.

However, every Curve Stroke brush I try to use Backtrack with no longer functions correctly. Strokes that insert geometry like the Curve Tube strokes no longer work correctly with this enabled, and other curve strokes simply disable their curve stroke behavior and perform like the standard brush above.

So yes, this is a glitch, but expected.

---

@Noren

Generally, what is the best method to report bugs? Here in the forum or directly to support? Will moderators log bugs reported in the forums?
Is there some kind of public bug tracker to check if a problem has already been reported besides doing a search in the forums?

The community forums are for discussions between other users, and are not used to track or report bugs. Technical issues and feature requests should be reported to Pixologic Support via support ticket (called conversations now). Common issues can also be found listed on the Support Site, however that site was just updated and those sorts of articles are a bit sparse at present. However, new users can usually benefit by first discussing their issue with other users first, to make sure something isn’t simply a usage problem, and not a bug.

[Noren]

Thanks again, Spyndel!

@Spyndel

You can apply a stroke to a curve by simply clicking on it with a brush that has curve stroke enabled. There is no need to drag on the curve, as this edits the placement of the curve . Again, do not drag on the curve unless you want to edit its placement. Just tap it.

Got it! This doesn’t seem to work with the pen and pressure sensitivity in my case, though, probably because it tries to apply the respective size and pressure and even the smallest unintenional nudge can twist up the curve significantly. I reset my brushes and the default behavior for e. g. the CurveStandard does cause this behavior.

So now I can apply the curve by clicking with the mouse, but can I also manipulate the curve without applying it?

@Spyndel

This is what you’re looking for. Read the Ctrl-mouseover description.

I’m afraid I simply don’t see a difference in behavior, no matter what the curve looks like. It doesn’t seem like there is some kind of option key for the bend mode, simply activating the button does the trick, correct? Do I need a special brush size or falloff settings for this? Tried around to no avail.

@Spyndel

You can enable both the size and intensity modifiers at the same time, but they’ll both be modified by the same curve. Zbrush is designed for use with a pressure sensitive tablet, and most tapering/variable intensity strokes will be the result of the pressure sensitivity.

In this case I’d prefer to have a continuous gradient over the length of the spline. Decoupling the curve for size and intensity should allow for more options, here.

@Spyndel

Backtrack and lazy mouse both disable just fine when you switch off LM.

Not for me, unfortunately. When LazyMouse and Backtrack were activated before and then only LazyMouse is deactivated (greying out the whole UI Group including Backtrack, implying it’s off ) and then Curve Mode is activated (for the same brush), Backtrack seems still to be on. This is apparent e. g. when using the backtrack plane mode on a sphere. Not a show stopper, but probably not the intended behavior.

[Spyndel]

@Noren

Got it! This doesn’t seem to work with the pen and pressure sensitivity in my case, though, probably because it tries to apply the respective size and pressure and even the smallest unintenional nudge can twist up the curve significantly.

It really shouldn’t be that difficult to just tap the stroke. Make sure you’re using a tablet that meets the required specs running Wintab drivers, and that your pressure sensitivity is functioning correctly.

However, you may have better luck by making just very light contact with the stroke, then after contact, press SHIFT to draw the line along the stroke.

Beyond that, you will need to contact support if you feel your pressure sensitivity is not functioning correctly. The community boards will not be able to help you with system specific technical issues.

---

@Noren

So now I can apply the curve by clicking with the mouse, but can I also manipulate the curve without applying it?

The behavior varies with the context of the brush that Curve mode has been enabled for. For a Curve Tube brush, you can drag the tube around all day without affecting the mesh. Curve Standard is a live sculpting brush though. You would either mask the entire mesh first, or reduce the intensity to zero to move the curve without affecting the mesh with this brush active.

Remember, it doesn’t matter how a curve was created. If you click on a live curve with a curve mode brush, that brush stroke will apply to it. So you could draw out a precise curve and edit it with the topology brush, then switch to the brush you want to apply the stroke with and click on it.

---

@Noren

I’m afraid I simply don’t see a difference in behavior, no matter what the curve looks like.

Quit the program entirely and restart it just in case something is glitched out. This is most easily seen with the Curve Tube brushes, as they have no pressure variables. Select the Curve Tube brush, and enable the Size modifier in Curve Modifiers. Draw out your stroke, and you should see the tube taper to a point. Now make a radical change to the Curve Falloff, and tap the curve again to update it.

Remember, the curve settings are on a per brush basis, and will need to be enabled for each brush you want to see it with.

---

@Noren

In this case I’d prefer

Again, feature requests go to Support. I dont develop the program, and the people that do are likely to miss suggestions made in any other fashion.

---

@Noren

Not for me, unfortunately. When LazyMouse and Backtrack were activated before and then only LazyMouse is deactivated (greying out the whole UI Group including Backtrack, implying it’s off ) and then Curve Mode is activated (for the same brush), Backtrack seems still to be on. This is apparent e. g. when using the backtrack plane mode on a sphere. Not a show stopper, but probably not the intended behavior.

Please re-read my original post. Lazy Mouse +Backtrack and Curve mode are two different things not meant to be used together, and will not function correctly if you try. If you keep trying to use them together, you will get this behavior. If you just use Lazy Mouse + Backtrack without curve mode enabled, you should not.

[Noren]

Thanks again for the many helpful tips!

Probably my tablet is to be blamed then. It’s an old Wacom Intuos 2 without official Windows 10 support. So far everything else has worked, but maybe it’s time for an upgrade.
Will look some more into Wintab. As I understand, it’s a Wacom initiative, but not sure when it was introduced.

I do realize you aren’t a developer, just wanted to lay out my reasoning.

As for the Curve Falloff, I was referring to the bend behavior that according to the documentation should be affected by it, I do see the size/intensity changes, but no changes in bend behaviour.

I’m not attempting to use LM, BT and CM together, I’m just seeing a behavior where BT “sticks” and affects CM when it was activated at any time before and LM was deactivated without deactivating BT prior. The interface suggests deactivating LM should deactivate BT, but that doesn’t seem to be the case.
E. g. choose the standard brush,
activate LM and BT set to plane
Deactivate LM
Activate CM
Try to use CM on a sphere. In my case, BT set to plane seems to be still active.

[Spyndel]

@Noren

E. g. choose the standard brush,
activate LM and BT set to plane
Deactivate LM
Activate CM
Try to use CM on a sphere. In my case, BT set to plane seems to be still active.

Stop activating CM, and the problem goes away. I don’t know how to make this clearer. This is the result of using two incompatible modes. Do not use Curve Mode with Backtrack+Lazy Mouse. They do not function together.

[Noren]

I think you are misunderstanding my intent regarding this. I’m not looking for a solution, I’m trying to confirm a bug.