Oculus Medium with Zbrush ---> VR to 3D print workflow

I've been using Oculus Medium a lot lately. This tool allows me to sculpt in an immersive environment and use gestural strokes in ways that are impossible with other software. I thought I'd do a quick write up for my workflow using Zbrush to get sculpts done in Medium ready to be 3D printed. I like my models to have flat bases and a low poly aesthetic, and Zbrush's Trim brush and Decimation Master make these modifications easily.

Oculus Medium Model.

Make sure to "export" the model inside the Medium software. This will create a .obj file in the Medium --> Sculpts --> [sculpt name] folder.

Import to Zbrush

Open Zbrush and import the.obj of your model, drag it onto the canvas, and press T to enter edit mode. The Oculus Medium and Zbrush world axes do not appear to line up, so the first thing I do is draw several transpose lines to realign the model to each Zbrush Axis. To do this, rotate the model and then hold shift so that your view snaps to either the X, Y, or Z axis. Next, press R, drag a Transpose line, then click and drag the red circle to adjust the model. Repeat this from several different angles to get the model aligned how you want.

The object with trimmed, flat base.

To make printing easier, I like to trim the base. Snapping the view to a flat side angle, hold ctrl (cmd) and shift, then click the brush icon in the upper left. Select "trim rectangle." Then, holding ctrl and shift, drag your rectangle over the area you want to trim. The result will be a flattened base like in the image above. The polygons are smashed, however, so the next steps will clean up and retopologize the surface for printing.

*Optional Step: If your model has stray polygons, small bits not part of the main model, etc. You will want to ctrl + shift + click on the main group of your model, then go to Tool --> Geometry --> Modify Topology and choose delete hidden.

*Optional Step #2: If you import a model with several layers, you will want to Dynamesh the model to merge them all together. Layers from Medium are imported as separate Polygroups into Zbrush. You can also select which Polygroups you want to keep, and remove the rest by hiding the geometry you don't want and then choosing "Delete Hidden." You might also need to "close holes" in case deleting polygons leaves gaps (this never hurts the model, so it's good practice to Close Holes whenever you delete geometry.)

Decimated model.

The model must be triangulated in order to be print-ready. Zbrush's plugin "Decimation Master" makes this easy. Go to Zplugin --> Decimation Master and click preprocess. This step will take the software a little bit of time while it analyzes the surface, so be patient, especially if you have a high (1 million +) polycount.

Once it's precomputed, you can decimate down to whatever level you want. I personally like a low-poly aesthetic, so I aim for about a 10-20k poly model (if the model is originally 1 million polygons, I'll choose 1-2% decimation.) If you don't want to sacrifice resolution, 20% is usually a safe number. Because the model's surface is precomputed, you can decimate, undo, change the %, and redo decimation until you are happy with the visible result. Shift + F will show your model in a polyframe mode, which is a helpful visual.

Lastly, go to Zplugin --> 3D print exporter, choose "update size ratios," enter a value for one of your model's dimensions (you can modify this is the printer software later, of course), then choose "STL" and save your file.

Now you should have an STL file from your original Oculus Medium sculpt that your printer software can handle more easily. 

Other notes: With your model in Zbrush of course, you can do a million things with it before prepping it for printing to add additional details or modify the surface. Medium can even be your starting point for a simple base mesh for going ahead in Zbrush.

Finished print on the printer, run through Simplify3D software and printed on a Flashforge Creator Pro with Hatchbox 1.75mm Blue PLA.

Supports have been removed, and a quick paint job applied. My sculpture / assemblage style can be messy and chaotic, so in this case I don't mind some of the stringing and broken parts of the model.

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