Curve Brushes

 Curve brushes are a hard surface tool that can be used both in Z brush alone or made in Maya and then brought into Z brush. They can be very useful for making repeating elements such as hair strands, belts, and other details with a definitive start middle and end.

Curve brushes are made up of 3 sections - 

- Top or the beginning element  of the brush.

- Middle or the section of the object you want to be replicated many times to increase it's length

-Bottom or the end  element of the brush

For example, In terms of a belt buckle, the top is the prong clasp, the middle is the belt, and the bottom is the connector clasp. Here is an example of this illustrated on a wire model. The Top is the USB connector, the middle is the wire, and the end is the type c connector.

 Red - Beginning

Orange - Middle

Yellow - End

To make a Brush, first model your top and bottom elements. then make your middle element separate to the top and bottom models. by pressing D, then holding down V when clicking on the top or bottom elements, you can snap the vertices of these elements to the vertices of the middle object. This will result in a model that looks connected, but is actually 3 separate elements. It is very important to note that you must make sure your model is vertically aligned, NOT like how the model is aligned in the screenshot above, If you do have it horizontally aligned, when you bring it into Z brush to make the curve brush, your top and bottom elements will be placed incorrectly. Make sure to export each individual element as an OBJ file then head over to Z brush to create the curve brush. Use the Subtool master option under the Zplugin dropdown at the top and click multi insert to bring in each of your OBJ files. Make sure to check for duplicates in the subtool menu on the side and delete any if there are. Then press the line fill option, then press Shift F to show the mesh of your subtools. From here you should press Ctrl W, to make a new polygroup, making sure to do this for each of your separate elements. Make sure they are aligned in the subtool viewer as Top, Middle, Bottom. Once everything is set up, merge down the subtools into one subtool.

Following on from this, find the stroke menu at the top of the screen, then select the curve dropdown. Toggle on curve mode and for something consistent like a wire or belt you shouldn't need to adjust any more settings, however if you want to model something like hair, you can toggle on the curve fall off for altering start and finish size. After this find the brush menu and the brush modifiers dropdown, make sure to toggle on weld points to weld together the separated elements. This should leave you with the result below. It is important to know that the smaller you make your middle element, the smoother the curve should look.

I had some trouble with this project and figured out that my model must be placed vertically in Maya before exporting else it won't work. After i had fixed the alignment issue, my brush worked fine.

I also figured out how to import something from Maya into Z brush - [Not used in this task]

1. Tool - Import - Select OBJ file

2. Select the triangles option

3. Drag into the work field.