Featured image of Blender: How to Reduce Polygons – Simply Explained
Back to Basics

Blender: How to Reduce Polygons – Simply Explained

Picture of Blu Siber
by Blu Siber
Jul 13, 2018

When modeling in Blender, models can sometimes have too many polygons, gobbling computer memory and adding an undesirable level of complexity. In this article, we show you how to reduce polygons in Blender.

Blender: How to Reduce Polygons What is an Object Modifier?

The result of adding, editing, and removing a modifier
The result of adding, editing, and removing a modifier Source: Blu Siber / All3DP

Object modifiers in Blender are properties that can be applied to an object. What makes them different from a tool or an add-on is that they change objects without permanently modifying them. That’s because a modifer acts as a feature on top of the base mesh. Then you can either delete the modifer to remove the changes or apply it to integrate the changes into the mesh.

For example, in the animation above, the modifiers tab — the one with the wrench icon — is already selected in the properties editor. With the monkey mesh selected, a modifier is added (subdivision surface, in this case) to change the object. Subdivision surface increases the poly count, smoothening the object.

Notice that the object can still be edited and viewed in the new state, though the modifier has not been applied. Indeed, the modifier is instead deleted, thus the object goes back to its original state.

Well, that’s how to increase the poly count. But how does one, in Blender, reduce polygons? Let’s take a look!

Blender: How to Reduce Polygons Adding the Decimate Modifier

The procedure of adding the the decimate modifier
The procedure of adding the the decimate modifier Source: Blu Siber / All3DP

The easiest and most common way of lowering an object’s poly count is using the decimate modifier.

  • First, locate the properties editor. If you’re using the default version of Blender, on the default view, you’ll find the properties editor on the right-hand side of the screen. You can also turn one of the editors on-screen into a properties editor. To do this, simply locate the editor type button, click it, and select “Properties” from the list. The editor type button is usually at the upper-left corner of the editor on a text-filled section, or on the lower-left corner of a graphics-filled section.

In this example, we’ll use a properties toolbox to the right of a 3D editor. Next, we have to add the modifier.

  • In the 3D editor, make sure your object is selected. (If it’s not, right-click on it to select it.)
  • (This procedure is shown in the image.) Click the wrench icon in the properties editor to go to the modifiers tab. Then, left-click the add modifier button. The list of available modifiers appears, and you can pick one by left-clicking, scrolling and middle-clicking, or pressing the keyboard arrows and hitting enter. In this case, select the decimate modifier.

Now we’re ready to start changing the values. Using the decimate modifier, there are two methods in Blender to reduce polygons in a mesh: edge collapsing or un-subdividing.

Blender: How to Reduce Polygons Method 1: Edge Collapsing

A demonstration of how the collapse reduces polygons
A demonstration of how the collapse reduces polygons Source: Blu Siber / All3DP

Edge collapsing works by selecting edges (where each edge is a line between two vertices) and converting them into vertices. Blender does this automatically by calculating which lines it can turn into points without changing the shape of the object too much.

  • To use this method, look at the decimate modifier. Just under the “Apply” and “Copy” buttons, you’ll find the different method tabs. Ensure that collapse is selected before continuing.
  • The ratio slider controls how many edges should be replaced with a vertex, demonstrated in the above image. It operates in decimals, where 1.0 means that 100% of the edges are left unchanged, and 0.0 means that no edges are left in tact. Naturally, 0.0 is almost never used as it makes the object look terrible.
  • Skipping a few advanced controls, the triangulate checkbox is another useful feature. When checked, any edges that are collapsed become part of a new triangle. This is especially useful for cases where the object needs to maintain an accurate size, not just an accurate look. However, it can also modify the object in ways that might make it look different than it did before.
  • The last notable control is the symmetry checkbox. When checked, it ensures that opposite ends of the object remain exactly alike. You can choose which axis on the object should be symmetrical using the button to the right of the checkbox.

This method is the best if your main goal is to get rid of extra polygons on a complex object. However, it’s not the best way to keep the object’s original shape.

Blender: How to Reduce Polygons Method 2: Un-Subdividing

A demonstration of how the un-subdivide method works
A demonstration of how the un-subdivide method works Source: Blu Siber / All3DP

This is perhaps the easiest method to reduce polygons in Blender, due to its one and only control: the iteration count.

As the name implies, this is the opposite of subdividing. Put simply, un-subdividing does two things: It deletes an edge between two faces, and then it makes a new face where the previous two used to be. Because Blender simultaneously performs several other operations to keep the shape of the object, this method works best if you want to keep the initial shape as accurately as possible, but with less faces and edges.

On the other hand, this method does not effectively reduce vertices, if at all. If that’s your goal, use the previous method, preferably with the triangulate option enabled.

Blender: How to Reduce Polygons Applying Your Changes

Applying a modifier of 75%
Applying a modifier of 75% Source: Blu Siber / All3DP

After you’ve used either method, and you’re content with the result, simply click Apply on the left-hand side of the modifier.

This rebuilds the mesh, using the settings you customized, and deletes the old mesh. As shown in the example, once the apply button is clicked, the modifier disappears, because the changes are integrated into the object. Of course, if you hit Apply accidentally, or if you change your mind, the “Undo” command will still work, provided you didn’t do anything in Blender after clicking Apply.

If you decide that you don’t like the results of your object before you apply the modifier, you can simply click the “X” in the top-right corner of the modifier to delete it. This removes the modifier without applying it, so your object goes back to the way it was before.

Presto! Now you have an object with less polygons to fool around with, allowing you do more with the object in a more simple way. Plus, it takes up less storage space and RAM. A win-win situation, both for you and your computer!

License: The text of "Blender: How to Reduce Polygons – Simply Explained" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.

Subscribe to updates from All3DP

You are subscribed to updates from All3DP

You can’t subscribe to updates from All3DP. Learn more… Subscribe

You can’t subscribe to updates from All3DP. Learn more…

Recommended for you