Clip Brushes

Clip Brushes

The clip Brushes are different from any other brushes as their operation is always perpendicular to the canvas. These brushes are similar to how the Eraser tool cuts away pixols on the canvas, except that they are used to cut away areas of your model and slice its borders. These Clip brushes do not change the topology of your model; they only push the polygons based on the stroke you apply to your model.
The Clip Curve brush in action, combined with radial symmetry.
Since the clip Brushes use open and closed curves, it is important to know which side the clipped polygons will be pushed to. For this purpose, the curves have a shadow on one side and polygons will be pushed in the direction of the shadow. If you create your stroke in the wrong direction, just press the ALT key to tell ZBrush that you want to push the polygons in the other direction.
The clip brushes respect masking. If you want to protect an area from being pushed, simply paint a mask on it. Don’t forget to check your model for unprotected areas as the clip brushes operate through the whole depth of the model relative to the curve.
When tapping the ALT key once with the ClipCurve brush you will create a curved line that can be changed in direction every time ALT is clicked. If you double-tap the ALT key when using the ClipCurve brush, the change in line direction will be a sharp angle rather than a smooth curve.
When holding the ALT key while using the Circle or Rectangle Clip brush, ZBrush will cut away all of the mesh that is inside the drawn circle or rectangle. Understand that if you hold the ALT key and the cross indicator is over any part of the mesh there will be a result of geometry being pushed out.
The clip brushes all share the same behaviors; only the Stroke type makes them different.

Clip brushes additional features

Stroke option
By pressing Ctrl+Spacebar while using a Clip brush, a pop-up window will appear offering two options:

• Brush Radius: When enabled, the polygons will be partially pushed to the line depending upon the brush size and the distance of the mesh from the camera.

• By Polygroup: When enabled, a polygroup will be created based on the pushed geometry included in the circle or rectangle stroke.

Brush Radius and By Polygroups are also located in the Transform palette.
Center position for Circle and rectangle Clip Brushes
When drawing a Circle or Rectangle stroke, a small cross appears in the middle of the shape. When the cross is outside of the mesh, the polygons are cut to the edge of the circle or rectangle to create a notch in your model. When the indicator is inside the mesh, polygons will be pushed out which results in an expansion of geometry rather than a cut.
1: The Circle Clip brush is used with the center of the stroke outside of the model. 2: The result, with the polygons pushed inside the circle. 3: For this new stroke, the center is inside the model. 4: The polygons are pushed outside the circle. 5: The same as 4, but at a different angle to show how the clip takes place relative to the canvas.
Note:
When pressing ALT while the indicator is inside the mesh, the stroke switches from white to black and the polygons located inside the stroke are pushed perpendicular to the screen, in both directions.
If you start to create a stroke and need to move it, hold the spacebar and move your cursor; the stroke will move. Release the spacebar to continue or finish the stroke.

Selecting and using Clip Brushes

As with the Smooth brushes, the Clip brushes are activated by hotkey. When selecting a Clip brush in the Brush palette, it will automatically be assigned to a specific hotkey: Ctrl+Shift.
When using a normal brush, press Ctrl+Shift to activate the last selected Clip brush. Release Ctrl+Shift to return to using the normal brush.
Selecting another Clip brush will replace the previously selected one without changing the active normal brush.

Clip Curve

The Clip Curve uses a curve to push the polygons. By default, this is a straight line.
Tap the ALT key to create an invisible point that will transform the line into a curve.
Image:.jpgBy default, the Clip Curve creates a straight line, which pushes all the polygons to the same plane.
If you want to create an angle at the point position instead of a curve, double-tap the ALT key.
If needed, press the space bar to move your curve while creating it.
Press the ALT key when releasing the cursor if you want to push the polygons on the other side of the curve, according to the curve shadow position.
On the left, the Alt key has been tapped once in two different positions to create the curve. On the right, the Alt key has been tapped once to create a curve and then tapped twice to create an angle.
The shadow of the Clip Curve must always be on the same side of the curve. Basically, the Curve pushes all polygons in the direction of the gradient side of the curve. A curve which looks like a letter “S” would not work as the curve gradient will reverse twice and produce an unexpected result.
On the top: Valid clip curves. Note that the bottom section of the last one on the right is at the limit of working. On the bottom: invalid curves which can produce unexpected results. The curve is crossing its shadow.
Note: It is not possible to edit the clicked points after they have been created.

Clip Circle

The Clip Circle uses an ellipse to push the polygons. By default, all the polygons outside of the circle will be pushed to the border of the drawn circle.
Hold the ALT key when releasing the mouse button if you want to push the polygons located inside of the circle. This will allow you to create clean circular edges in a mesh’s existing hole. (The clip brushes cannot be used to create holes in topology, but they can reshape existing holes.)
By activating the Center and Square features in the Stroke Palette you will draw a perfect circle with the center located at the initial brush click.
If the Middle Cross indicator is over the mesh when holding the ALT key, the geometry within the circle will be pushed out instead of being clipped.
If needed, press the spacebar to move your curve while creating it.
Note: It is not possible to edit the clicked points after they have been created.

Clip Circle Center

Clip Circle Center is the same brush as Clip Circle, except that the stroke creates a perfect circle using the Square and Center options located in the Stroke palette. By default, all the polygons outside of the circle will be pushed to the edge of the drawn circle.
Hold the ALT key when releasing the mouse button if you want to push the polygons located inside of the circle.
If needed, press spacebar to move your curve while creating it. Note:
It is not possible to edit the clicked points after they have been created.

Clip rectangle

Clip Rectangle uses a rectangle to push the polygons. By default, all the polygons outside of the rectangle will be pushed to the border of the drawn shape.
Hold the ALT key when releasing the mouse button if you want to push the polygons located inside of the rectangle. This will allow you to create clean square holes in a mesh that already has a hole. (The clip brushes cannot be used to create holes in topology, but they can reshape existing holes.)
By activating the Center and Square features in the Stroke Palette you will draw a perfect square centered on the initial brush click.
If the Middle Cross indicator is over the Mesh when holding the ALT key then the geometry within the rectangle will be pushed out instead of being clipped.
If needed, press the spacebar to move your curve while creating it.