applying a custom texture in ZBrush

I like designing fabricated or cast jewelry with custom glass cabochons, which can be done pretty easily in ZBrush.

After creating your pendant through whatever means you’d like…sculpting, hard surface modeling, the easiest method is to create a separate subtool that represents the stone. It can also be done with a separate polygroup, but my preference is the separate stone which can be duplicated and different cabs tested.

In the image above, the first piece features a cabochon created from a pâte de verre (glass paste) test tile from the fabulous Alicia Lomne’s class I took last October. The second example is a slab of fused glass that I created a few years back that I cut into cabochons, and the final one is a piece of Fordite. Never heard of Fordite? It’s a manmade “stone” from the drippings of automotive paint from factories, and it is sparkly and beeeautiful! You can actually tell the “vintage” by the colors of paint in the layers; for example, a piece of Fordite from the 1970s will look totally different than a chunk from the early 2000s.

Anyway, your setting for your stone can be as simple as a bezel from one of my bezel tutorials, and create the matching cabochon. I’ll make a video tutorial here shortly to make the pendant above, which was made using the Project Primitive tool, which can be found above the Gizmo 3D in the Move mode.

Moving on…the key here is to apply a material to all subtools before you begin. While in the Draw mode, choose the M button to the left of ZAdd. This enables your material channel. Next, choose MAHmc_Shiny from the Materials picker on the left, then from the Color menu, choose FillObject. If you’ve loaded my custom interface, there is a button on the left under the color pickers for this function.

Now go to the cabochon subtool, and pick a material such as SketchShaded3, then click the FillObject button again. This will assign the material to the cab before we load the texture, giving you a clean slate.

Now, switch to the Rgb channel. Go to the Texture picker on the left side of the canvas. Choose Import at the bottom, and load your texture.

1. Choose a brush that you don’t use often—I use the Clay brush since I usually use ClayBuildup if I’m sculpting.

2. Switch FocalShift to -100, which will prevent the texture from being blended around the edges.

3. Choose DragRect from the Stroke menu, which will allow you to click on the model and drag to resize the texture.

4. Make sure that the desired texture is loaded under the Texture selector.

5. Click on the cab and drag to apply the texture. You can resize and rotate as needed.

To view your piece in all its glory, Choose Best from the Render menu. If you’d like to save the image, go to the Document menu and choose Export.

If you’d like to try different cabochon styles, duplicate the cab under the Subtool palette. Use visibility to turn the different cabs on and off, then export each one.

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ZBrush pendant with labradorite cabochon; stone image applied as texture

If you’re a graphic designer and want to place your pendant on an alternate background like the image above, you’ll use a “mask” to block out the background in ZBrush. To create a mask, use the BPR render button on the upper right-hand corner of the canvas, then go to the Render menu, look for BPR RenderPass, and look for BPR Mask…click the button and name the file “[whatevername}_mask.psd. Immediately after generating the mast, make sure it’s set for a “Best” render under the Render menu, then export the image again. If you’re unfamiliar with how to use a mask in Photoshop, do a quick search online for “Using alpha channels in Photoshop.” This will allow you to have a version of your ZBrush jewelry without a background, ready to insert into a custom background.

I’ll get a video up shortly that has this technique, but hopefully this will point you in the right direction for adding cool textures! Try it with veined turquoise or a Mexican Agate, just for fun…

Same texture applied in a different orientation on a pair of earrings

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(2) Ocean Jasper cab image from eBay seller waly-beads.
(3) Crazy Lace Agate image from Silverhawk’s Designer Gemstones.
(5) Ocean Jasper from MagicStones on Etsy

the rubber chicken pendant

I haven’t blogged in awhile because I’ve been remodeling my parents’ house. But while preparing a portfolio piece for a jewelry company, I made a series of sheets that show the design process of some of my more recent work.

Click to download the PDF of this file.

So how did I make this little guy? I started with a DynaMesh Sphere from the Lightbox, then turned off Perspective. I used the Gizmo 3D in the Move mode to stretch the sphere into an egg shape.

Switch to the Draw mode. Using a mask where the neck should go (Cmd on Mac, Ctrl on PC), I reversed the mask (Cmd/Mac, Ctrl/PC and click on background) and used the Gizmo 3D “ball” in the Move mode to pull the neck out. Since your primitive is already a DynaMesh, after each major change, re-DynaMesh to refresh the mesh. If you want to see what’s happening, on the right side of the main canvas look for the PolyF button with a grid on it.

Using the same method, turn on Symmetry under the Transform menu, then you can mask off both legs at once in the Draw mode, then switch to the Move mode and use the Gizmo to pull the legs down.

Try using the Snakehook tool to pull out things like the toes on the feet…play around with the size. The shortcut for Snakehook is B-S-H on your keyboard.

Switch to the Clay Buildup tool for sculpting details…a good tip is to turn your intensity down to 5 so it doesn’t apply much material, which is easier to smooth with the shift key. The keyboard shortcut for Clay Building is B-C-B.

The arms were masked off, mask reversed, then pulled out to each side. Try using symmetry to do this, but you will need to move the Gizmo to the general vicinity of one of the arms…when you pull out to the side, it will “raise” both arms at once. To move the Gizmo, hold down Option/Mac or Alt/PC and drag the Gizmo over the masked area for one of the arms, release the key, then use your mouse to pull the horizontal arrow away from the body. Clear the mask and fine-tune with sculpting. To re-center, click on the third icon above the Gizmo to find unmasked center.

Another trick? After masking, you can hold down the Cmd/Mac or Ctrl/PC and click ON the model to soften/blur the edge of the mask. This will provide nice, rounded arms.

And finally, the t-shirt was applied to the chicken using a mask and the Mask Pen. Try switching the stroke to Lasso if you’d like. Sharpen the mask by clicking on the model while holding Cmd-Option/Mac or Ctrl-Alt/PC. Then use the Extract command from bottom of the SubTool palette.

I’ll do a tutorial on this one soon, but hopefully this will get you started!

physical size, resolution, and file size

I've been out of touch for a little bit as I took on a pretty big project that's completely unrelated to jewelry. If you read my bio, you might have seen that I have a background in construction (of all things!). I've been in the middle of a major remodel of my parents' house, getting it ready to go on the market. If you can imagine, popcorn ceiling removal, paint, a new multi-level deck, and a total re-do of four bathrooms, including moving walls. If you've ever watched that show Fixer Upper, it's kinda like that...except for unlike the show, it doesn't happen over the course of an hour.

size matters

Yup, size can be a big issue when working with ZBrush. While I don't have a formal answer why, I'm guessing that it's because the program was designed to make things that were abstract—things that lived in a virtual world. So for that reason, size is relative in ZBrush, and measured in plain ol' units. Here you can see the Size sub-palette under the Geometry palette on the right-side of the interface.

The pendant on the stage (only the pendant, not the chain), is a minuscule amount smaller than 25.4 units. Well, if you count this as 25.4 millimeters, this equals one inch across. You can also see the Z Size is 1.61 units, so approximately 1.61 mm thick, which is a nice thickness for a pendant. And likewise, the height is 16.7 mm.

When I first started working with ZBrush, I saw a tutorial that suggested calibrating something called the Transpose Line tool. I struggled with this, and every time I thought I had the size correct, something would change and everything would be off. I couldn't reliably gauge bezel cups or stone settings...or even thicknesses. This also became an issue with the amount that a design or text was raised off or inset into the surface. So finding a way to make this work was really important.

Someone also asked me on YouTube if I used a plugin called "ScaleMaster." The answer is no. I have also tried RingMaster, another plugin, which is nice, but I also had some problems with that. However, I DO use RingMaster to insert gemstones because the models contain minimal polygons, meaning they don't slow ZBrush down.

getting started with a correctly sized model

So here's the process I use:

1. From the right-hand side of the stage, click on the yellow "S" that represents the SimpleBrush tool.

2. Choose the Cylinder3D from the list.

3. Click and drag a cylinder on the stage. It doesn't matter how large you make it...it comes into ZBrush at an XYZSize of "2" units.

4. Immediately press the "T" key to switch to the Edit mode.

5. Press the Make PolyMesh3D button toward the top under the Tool palette.

6. Look under the Geometry palette on the right-hand side of the window for the Size sub-palette.

7. Enter "10" in the XYZSize box and hit return to accept the new size.

8. The primitive is probably taking up the whole window, so click somewhere on the stage to deselect the number in the XYZSize.

9. Now press the "F" key to fill the stage with the current object.

And there you have an object on the stage.  It's pretty faceted, and not smooth, but we'll deal with that next.

smoothing the primitive

I have a special technique that I've developed to get a smooth object as soon as possible in the workflow. In the beginning, I thought simply performing a DynaMesh operation would smooth it, and I went back and forth between DynaMesh and Polish Features, but with results that weren't efficient or acceptable. So here's how I smooth things out.

1. Look for a button labeled Divide from the Geometry palette.

2. Make sure that the Smt button is turned on (this will smooth your primitive).

3. Click the Divide button twice.

4. Look above the Divide button for another button labeled Del Lower. This will delete the two lower-resolution subdivisions that you just created.

That should give you a nice, smooth primitive. 

before the Divide command

after dividing once...

and dividing twice...

So what happened? Each time that you use the Divide command, ZBrush takes each rectangular polygon and divides it into four polygons. Then when you divide again, it divides each one of those resulting polygons into four more polygons. If you have the Smt button activated, it takes the opportunity to smooth out your model.

You can see the underlying geometry of your model by using the Draw PolyFrame (Shift - F) button to the right of the stage, toward the bottom of the vertical row of buttons.

Subdivisions are wonderful if you're roughing out a shape, then switching back and forth between lower resolution subdivisions and higher resolution subdivisions. Adding material with a brush like the ClayBuildup brush works faster when working with a low resolution. But finer details are better applied with the higher resolution. I'll address this in a tutorial later.

Take a look at the example below...look at the pixillation of the cylinder and the number of ActivePoints. Each time that the cylinder is divided, it QUADRUPLES the number of ActivePoints. This has implications with regard to file size...our strategy is to get a smooth resolution while still keeping the file size down. 

So keep this in mind, and I'll write a little more later...then we'll talk about how working in actual size relates to your DynaMesh resolution. and how you can work more efficiently and on lower-end hardware.

Heck, I can even run ZBrush on my 2012 MacBook Pro! And you know what that means? I can sit in a café in the Caribbean and design jewelry. SWEET!

an experimental earring from a kaleidoscope program

I'm just putting this experimental earring up here because I think it turned out pretty cool! Created in the new ZBrush Core.

I used a kaleidoscope drawing program that I found on the internet to make the basic design, used the Gaussian Blur tool in Photoshop to blur the jagged edges, then Unsharp Mask to bring it back into focus. The design was then brought into ZBrush as an alpha mask, turned into a polygroup, isolated, then extracted. The resulting mesh was then Dynameshed so it could be sculpted, then divided (using Subdivisions and the Divide function) to give a finer mesh for sculpting.

UPDATE: I’m now using iOrnament on the iPad with the Apple Pencil as a design tool for repeating patterns and mandalas. It eliminates the problem of having to blur the image and sharpen…just use AirDrop and send it over to your computer!

BIG DISCLAIMER: I wouldn't say that this is my best design work, but it was more of an experiment...so carry on.

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Rendered image from ZBrush

I used the Helix tool in ZBrush to create the coil on the drop, added some jump rings, then brought in a Cube primitive and Dynameshed it so I could draw a mask and create the darker supports that would recess into the background after a patina was applied. The original supports were straight. The curls add a nice touch that mirrors the swirls on the main design.

By the way...using the MRGB function in ZBrush, you can "paint" different areas to mimic the patination applied during finishing. Just choose a material, and change the color to a darker gray. This behaves a little differently than using the "dirty" silver MatCap material, and results in a more dramatic presentation of the finished piece.

UPDATE: When this earring was printed and cast, it was too thick and too heavy. Thanks to the technology, I was able to shrink the thickness, enhance the scrolls, and reprint. The great thing about having a printer on your workbench is being able to make adjustments and test techniques. 

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The models with supports added, ready to print. This version was too thick and too heavy.

MoI — moment of inspiration CAD software

types of CAD modeling

After taking an online course on jewelry in ZBrush, I was a little frustrated that the instructor was going back and forth between ZBrush ($795) and another piece of "parametric CAD" software that was more expensive. I had a few early attempts to stretch SketchUp's capabilities to make basic forms for ZBrush that worked okay, but since then I've learned more about ZBrush's ZModeler functionality for hard surface modeling.

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Simple flower made in virtual "clay" in ZBrush

So you say, "Kat, you're using that crazy terminology again, and I have no idea what you're talking about." Let me explain.

ZBrush gives you the ability for more freeform modeling. Imagine sculpting with a ball of clay in real life...you can push and pull the material into organic shapes, creating a model in a very realistic way but in a new medium. The flower shown here is a very basic example of this type of freeform modeling in ZBrush. However, the flower was originally created in ZModeler as a hard-surface model, then sculptural details added with other more freeform brushes.

The ZModeler mode in ZBrush is great for creating hard-surface models...this would be like modeling a starfighter...you might start with basic shape and push and pull surfaces to make something more mechanical looking. Here's a fascinating time-lapse video of "Alex O" modeling a war helmet in ZBrush with ZModeler. In jewelry design, I might use the ZModeler functionality to create a square frame for a pendant, then an inner medallion, then switch over to soft sculpting to create the design. When creating a base for 3D printing, I also use the ZModeler functionality. Here's another great video from Alex O that shows him using ZModeler to make a geometric ring.

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However, something like SketchUp (SketchUp Make, FREE download) is a little more rigid. I can create a box, then push and pull geometric shapes. But if I were making a box that I wanted to be exactly 20 cm, I have a precision built in to the program that can make that happen. That is a characteristic of a "parametric" 3D modeling program. That makes SketchUp...like AutoCAD, Fusion360 (cloud-based, FREE for hobbyists), Solidworks, and similar software...perfect for creating technical drawings and product designs. For example, I used SketchUp to design my jewelry workbench.

moment of inspiration (MoI)

I had some issues with creating printable models in SketchUp, so I started looking around for another "technical" drawing solution that wouldn't break the bank. Enter Moment of Inspiration, also known as MoI. MoI is $295, works on both Mac and PC, and has a 30-day trial.

At first I was a little skeptical. The interface was pretty basic, and definitely wasn't written to take advantage of the Mac interface I'm using. But then again, neither is ZBrush. After a couple of YouTube videos I was up and running, and I was able to figure out the rest on my own. 

So what is MoI good for? Probably almost any kind of technical modeling you might want to do except freeform "clay" type modeling. You could take a freeform "extruded" shape and "subtract" a sphere from it. Combining different "primitive" shapes, such as cubes, cylinders, and spheres, you can make pretty complex models that export well. Turning on a "grid snap" or "object snap" helps line things up. Then you can export these items easily, bringing them into the PreForm or other "slicing" software that prepares the file for 3D printing.

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Some rubber mold frames made in MoI

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I jokingly say that the second phase of having access to a 3D printer is when you start making your own tools. I purchased some frames for making rubber molds from Rio Grande, but they were too wide to fit in a nifty little spring clamp that holds the split mold together while filling with hot wax. Additionally, trying to estimate the amount of two-part "RTV" (room temperature vulcanizing) mold material usually resulted in wasted material...and at $56 a container, it's too expensive to do that! So my "improved" version has markings on the side to indicate centimeters, and a handy spreadsheet calculates the exact volume and weight of RTV needed. Remember the ability to measure in a parametric modeling program? Because MoI works that way, my one centimeter marks are accurate when printed. In ZBrush, that would be more difficult.

And because I'm a dork, I added www.katkramer.com and my logo to the side...and it was backwards, so when the rubber mold is made, my website address doesn't read correctly. Oh well, there's always version 2.

So in a nutshell, MoI is a nice little program, and the models created are accurate in size. It is a nice alternative to more expensive programs for making basic models to bring into ZBrush.

finally casting...the mandala pendants

UPDATE, December 2017: Looking back at this post, there are so many things that are wrong! Anyway, a good exploration of what works and what doesn't, and modifying a design to cast and finish more easily. The main change I eventually made to this pendant is to attach the design to a backplate, so the design is simply raised from a background. With a patina, the design is similar but much easier to cast and finish. I have since scrapped this design and melted them all down. So maybe they'll be collector's items someday! And oh my goodness…thankfully my design skills have come a long way. I’ll leave this post up, though, just in case others are having the same issues.

Well, it's finally time. What better time to start casting holiday gifts than a week before Christmas?

It's been an interesting journey. It started back in Denver after I got the casting setup...I remember that my first attempt at casting with a perforated flask, I ran out of acetylene at 1 a.m. and didn't have a way to heat enough metal to cast. The second attempt, I realized that my acetylene/ambient air torch couldn't heat enough metal hot enough to cast. After switching to my old Smith Little Torch (acetylene/oxygen) with a "bud tip," I was able to get the metal melted, but never cast before we suddenly moved back to Texas.

Fast forward over a year. Since then I've taken the wax-working class with Kate Wolf, learned ZBrush, and explored printing in 3D on the Formlabs Form 2. I've printed a lot of things, but the missing link was casting them into metal jewelry.

So I was ready to go! Treed up some models, was burning them out, and my kiln fell victim to the outdoor sprinkler. Since I work late at night usually, I didn't realize that the sprinkler was scheduled to water the lawn that night. The kiln was sitting on a little window in the outdoor kitchen burning out my first 3D model flask, and a poorly aimed sprinkler doused the kiln and killed it. I awoke to an error message and a flask that hadn't completed burnout. I was crushed.

So what do you do when your Paragon SC2 kiln has been watered? Let it sit for a few days and let it dry out. Since this kiln has a metal cabinet, I removed the back and aimed the fan on the inside. Sure enough, about four days later I had the guts to turn it back on. It worked.

Next, I was ready to cast the 3D prints. I prepared the trees, the flask, and tried casting again. I was still having difficulty getting the metal heated correctly. About that time I was helping my parents downsize their house, and my dad gave me a little present...the Kerr Electro-Melt that I needed to get the metal to the right temperature for casting. Something I've learned through research—not in practice—is that metal can be porous if overheated. When melting with a torch, you don't really know how hot the metal is. Any casting I've done in the past was on a very small scale, and I probably just got lucky!

Incomplete casting

So I was ready to cast, and treed up some nine models. This time when I cast, I heated the sterling silver to about 1740°F (Kerr recommends going 100°F above the melting temperature of the metal, and silver is about 1640°F). I used the Formlabs castable resin burnout schedule, which clocks in at about 14 hours, landing on a 900°F casting temperature with a 3.5"x4" perforated flask. The result was not good!

But why?

After consulting Creative Side Jewelry Academy here in Austin, and the Formlabs forum, I found that it could be either the metal was not hot enough, or the flask was not hot enough. I found in another article that the flask can drop about 100°F in one minute in a vacuum caster, so it suggested making your flask temperature 100°F hotter. Also, filigree designs require a slightly hotter flask. The girl at Creative Side asked if I cast close to 1100°F, and I remember casting at or near that temperature in the past. Participants in the forum suggested between 900°F, or 950°F for filigree. Then the suggestion that every casting situation is different and these numbers are just guidelines, so it requires experimentation. 

Fast-forward two years later, and my settings now are this: flask temperature at the end is 975°F, and metal in my Kerr Electro-Melt is 1865°F.

So I set off to cast again. This time, I used two 2"x2.5" flasks, a 2.5"x2.5" flask, and a 2.5"x3" flask, each with three models, rather than trying to cast a tree with ten models (or more?). I also tried adding a forked sprue coming into the bezel on the back, and another configuration with four sprues coming to the back of the frame. On that one I also added two small sprues coming into the back of the bezel. The sprues on the back of the frame are very easy to clean up, but when I 3D printed this one, the different support configuration distorted the frame on the bottom.

I also conquered my fear of cleaning up the jewelry! I learned from the forum that I should try tumbling the pendants for longer (these were polished about 40 minutes on a rotary tumbler), and silicone wheels work well for cleaning up raw castings. So far I hadn't had much luck with them. So I busted out the kit and it worked!  I also tried these little wheels made with 3M micron finishing papers, and they worked well for grinding down the sprues from the back and finishing the back of the frame. And something surprising...the back of the pendant with a patina is as pretty as the back...so it's reversible. I'll have to play around more with that.

However, they were still usable, and became Christmas gifts!