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I'm a product designer (mould maker), trialing ZBrush and have a couple of questions

ZBrush Usage Questions
#1

Greetings all,

I have been working through some basic tutorials for the past week. I was well aware of the confusion encountered by many new users, so I’ve spent a week working through basic tutorials to get past the whole 2.5D confusion stage, and am now familiar with the basic tools and navigation.

I have a few questions relating to the work I do, which I have not yet come across anything specific, so I thought I’d see if anyone could point me in the right direction (even if it’s only a tool or keyword for me to search, rather than a full-blown tutorial).

The bulk of my job is creating designs which end up as moulds, made out of a rigid plastic. Generally speaking, the designs must have a flat base/back, and have no overhanging parts, as this will prevent the item falling out of the mould once cast. Also, to aid removal as well as CNC milling, a draft angle must be included, as we can’t machine vertical sides, and it would also result in the product refusing to leave the mould. I currently work with Lightwave 3D, but am wondering if ZBrush would complement my workflow for some more intricate or organic designs.

Q1… In ZBrush, can I trace the outline of an imported image, and create a 3D object with a flat back and front, and a consistent bevel all the way around? Either extruding a 2D outline and bevelling by a certain angle, or (for example) insetting by 1mm for every 10mm thickness…? I could do this in Lightwave, and import it, but if it can all be done in one application, so much the better.

Q2… To maintain a flat back and most of the bevelled edges, I am thinking about simply masking off this particular area. Unless there’s a better way I haven’t come across yet…?

Q3… Volume. I have to produce designs which will result in a final product with a specific mass. I know the weight per cubic cm of the material, so I’m wondering if there is a feature buried in the 3D printing tools whereby I can check the volume and/or mass of my design?

I think those are my big questions for now… Thanks in advance for any enlightenment you can share.
:slight_smile:

Regards,

Derek

#2

Hello DMG,

I’m a ZBrush generalist, and familiar with the output-specific concerns you’re mentioning, but am not a specialist in that area. I would encourage you to look for specialist resources devoted to other users doing the same type of work who have already solved these issues. It is possible that someone else working for the same field may notice your post here and help you, but it’s not especially likely.

To start, the Draft Analysis feature is designed to aid you in that type of work, and would probably be useful.

If you import a vector image, this can be used to extrude that image into 3D geometry with which you can specify a consistent bevel with the 3D Text and Vector shapes plugin.

Otherwise, there are multiple ways to create a 3d mesh out of a 2d raster alpha, multiple ways to isolate and select the area of a mesh that you want to displace based on a 2d alpha, and multiple ways to bevel geometry, but this will be a multi step process involving many different features. There would be no single-button approach here.

I’m not sure what you’re asking here. You would have to illustrate your question further. But yes, masking is one way to protect geometry from being affected by sculpting operations in ZBrush.

Yes. The report generated by the Analyze Selected Subtool in the Transform palette checks if the mesh is watertight, and returns volume and surface area for the specified dimensions.

Good luck!

#3

Q1 & Q3 Many, many ways such as Spotlight alpha project, Qmesh and so on. With these methods, since the front and back faces are connected by a ring of polys with no edge loops, it’s easy to mask the bottom and scale the top surface in plane with the Gizmo. This gives you the draft you need. If you use different polygroups for each of top, bottom and side polys then it’s east to mask the bottom so it stays flat, if it started flat, or to flatten it if it’s a bit off. Perhaps even oversize the extrusion and then use the knife brush to cut away the excess on the bottom to ensure a flat bottom that retains draft.

Check out Michael Pavlovich’s Intro to Zbrush for how to use all these basic features. Also search his What’s New in Zbrush series for each release for the knife brush, draft functionality, and so on.

#4

Thanks for the replies,

As Spyndel has suggested, maybe an image will help explain better what I’m after.

ZB-Bevels

Here, the yellow polygon represents the initial outline of whatever project I’m working on. Sometimes I will bevel up and in, sometimes down and out, as shown by the first two objects. I tried ZBrush’s 3D Text and Vector Shapes plugin, but it’s ‘bevel’ gives me the third option, where it has ‘rounded’ the extrusion rather than produced a draft angle.
To help Spyndel understand what I’m after, I’d want to sculpt the top of the object, without making the draft angle any steeper, so I’d need a way to ‘freeze’ that. I think Tobor8man’s suggestion of polygroups sounds worth looking into.

I found the stl tools, where it gives the volume. It’s giving me the volume in cubic mm though, which isn’t great, but I’m hoping there’s an option I haven’t come across yet to adjust ZBrush’s unit measurements.

And between the two of you, you have named a few tools which will hopefully be relevant, and I can go away and work through some tutorials for those.

Oh, and just to give you an idea of the kind of stuff I get to do , here was one of my favourite projects I did on a freelance basis - the chocolate dragon egg given out in the UK to mark the last season of game of Thrones.

GoT-Egg-ortho-lr
T4AFXG
:smiley:

Thanks very much for your help so far.

Derek