[Introduction to Blender] Using modifier tools (2) Generate (Build/Decimate/Edge Split)

Friday July 2nd, 2021

In this article, I will introduce how to use following functions.

Build (Build)
Decimate (Reduce polygon count)
Edge Split (Edge Separation)

*The version of Blender used in this article is 2.92.

This article is a continuation of the previous introduction article, so if you haven’t read the previous article yet, please go ahead and look at that one first.

[Introduction to Blender] Using modifier tools (1) Introduction – Generate(Array/Bevel/Boolean)

1 Build
2 Decimate
3 Edge Split

Build

Build is a function to make an object appear gradually in an animation.

Build

Start Frame	Start frame
Length	Length of the animation
Reversed	Play backwards
Randomize	Display randomly

The value of Length is displayed as the number of frames.
For example, if you set this to 100, the animation of the object appearing will be played over 100 frames.

Reversed plays the animation in reverse.

Reversed

Checking the Randomize checkbox will randomize the appearance of objects.
Changing the seed value will change the order in which the polygons are randomly displayed.

Randomize

Since the granularity of the objects appearing in the animation depends on the number of polygons, this cube has been subdivided in advance using the Subdivide function.
Subdivide is also present in the modifier, but it can be easily applied by switching to Edit Mode with the tab key, then right-clicking and selecting Subdivide.
Note, however, that this method does not use the modifier tool and cannot be re-edited.

Subdivide

Decimate

This function allows you to reduce the number of polygons and vertices in an object with a large number of polygons.

Decimate

Collapse	Apply almost evenly to the entire object
Un-Subdivide	Reverse subdivision
Planar	Planarization
Ratio	Ratio to apply
Symmetry	Symmetry around a specified direction
Triangulate	Triangulate polygons
Vertex Group	Specifies a vertex group

You can use Collapse to reduce the number of polygons by changing the Ratio value.
The Face Count item shows the number of polygons.
In this case, I downloaded a model of the sculpture from Sketchfab and used it.

Select the model you downloaded and click Import OBJ.

Add Decimate from Add Modifier on the right side of the screen.

Changing the value will also change the polygon count.

Adjust the Ratio value between 1.0 and 0.0 (one polygon).
The more you reduce the number of polygons, the rougher the surface will be, so it’s best to keep an eye on it and change the value little by little.

Edge Split

As the name implies, this function allows you to split edges. If you use this function on a cube by default, all edges will be split, but you can change the setting to apply it only to some edges.