Reducing Polygon Count Tips and Tricks

[Robin3D]

Reducing polycount on your designs

We’ve all been there, we had a model that needed some nice smooth curves or very fine detail so we’ve upped the amount of poly’s in the model by running the smooth modifier once or twice, or maybe 10 times.

Doing this can result in a 3D model with a filesize of hundreds of MB’s. Before you upload this file to 3D Hubs you will have to bring down the file size to below a 128 MB’s because this is our current maximum. But really, no 3D printable model should have to be over 100 MB’s because the extra poly’s simply won’t have any effect on the 3D print. Higher complexity models also take longer to print.

Removing all the extra poly’s by hand can be quite an undertaking, but have no fear! This guide should give you some tips on how to easily remesh/decimate your model to reduce the polycount but retain the same amount of detail.

Autodesk Meshmixer [Free]

1. In order to reduce the polycount using Meshmixer you have to import your .STL file

2. Select your model by double clicking on it

3. Then click reduce and drag the slider over to the percentage of polygon’s you would like to have remain. Usually 80% is a good amount that will still preserve the polygons that determine the shape of the model.

Before:

Polycount: ~1.5million

After:

Polycount: ~420,000

Alternative:

Under the sculpt tool, select bubble the Bubble Smooth Brush. Reduce the Strength and Size so you dont effect the model too much. Then, up the reduce count under the ‘Refinement’ tab. Using this method, you can manually reduce the polycount of certain areas instead of the whole model.

MeshLab [Free]

1. Load your model into MeshLab

2. Select from the menu: Filters - Remeshing, simplification and construction - Quadratic Edge Collapse Detection.

Pixologic’s ZBrush [Paid]

1. Import your model as a SubTool in ZBrush (Right hand side)

2. From the plugins menu, select Decimation Master

3. Pre-process all SubTools

4. Set the percentage of polygons that you would like to keep 10-20% is usually a good starting point.

5. Decimate the model

Extra tip: ZBrush also has an exporter for 3D Printing which will allow you to export your model as an .STL file. Make sure you also select the size you want your model to be exported at before uploading your model to 3D Hubs.

[gabriela3d]

Thanks for the great tips, Robin! Andy @DiMarzio these look like something right down your alley

[DiMarzio]

Just from my experience: The Zbrush 3D Print Exporter plugin sometimes has this weird thing were as you have something that’s, let’s say, 50mm in height, it will export to 5mm… I just had a few times, not a lot…That’s why I personally always doublecheck this in for example Netfabb (or something similar) just to be sure. In Netfabb you can also easily scale multiple objects at the same thing keep it’s relation/ratio. Also, a thing to keep in mind in Zbrush using the 3D Print Exporter plugin is that when using the plugin, you change you measurment first (inch or mm) and then firstly click on Update Size Ratios . This will calculate it’s real measurement of you object as it is in it’s present state. After that you can change the size and and when export it, it will have the correct size Nice to have tips around!

[DiMarzio]

Well, it is in my alley haha even right in my house! Love Zbrush!

[petervl]

Such a happy face

[Dom1nic]

Thanks! This was very helpful to me

[Starwind0]

There seems to be a missing step between 2 and 3. What is “reduce” ? It does not show up when one selects their model.

[Robin3D]

Hi @Starwind0, it can be a little confusing seeing as Meshmixer has “Edit” in two different spots within the program. First, use the ‘Select’ button on the left hand side. Then, double click your model (which will turn your model into a dark shade of orange) and a new menu should pop up on the left hand side that at the very top says ‘Edit…’. Third from the top after clicking ‘Edit…’ says ‘Reduce’.

I hope this was useful.