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Cell Fracture Add-On Automatically Decimates Base Mesh
Needs Triage, NormalPublic

Description

System Information
Operating system: Windows 10 Home 64-bit (2004)
Graphics card: GeForce GTX 1660 SUPER/PCIe/SSE2
version: '4.5.0 NVIDIA 460.89'

Blender Version
Broken: Version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: 0f45cab862b8, type: Release
Worked: ...

Addon Information
Name: Cell Fracture (0, 2)
Author: ideasman42, phymec, Sergey Sharybin

Short description of error
Running the Cell Fracture add-on on high-polygon triangulated or quad base mesh (such as 3D scanned model) results in fractured objects that are highly decimated/reduced as compared to the original base mesh they were born from.
Before Fracture

After Fracture

Exact steps for others to reproduce the error

  1. Import high-poly STL or OBJ to Blender
  2. Create simple particle system for object with particle source set to Volume.
  3. Run Cell Fracture add-on from Object Menu>Quick Effects>Cell Fracture with default settings
  4. Resulting fractured objects are highly decimated. If the object being fractured consists of all quads, it will be automatically triangulated and decimated to a lower-poly version of the original mesh. If the object is already triangulated, it will be decimated.

Additional Info:
It seems that at least one previous version of the Cell Fracture add-on had a "Simplify Base Mesh" option that has disappeared from the current version of Blender. This option is also referenced on the add-on's description page.

It would be beneficial to be able to utilize this add-on and maintain the original topology of the base mesh in the fractured objects.


Wondering if anyone here can offer some advice on the Cell Fracture add-on.

I am trying to fracture some very high-poly triangulated 3D scans but it seems that the Cell Fracture add-on takes it upon itself to simplify the base mesh on it's own and the resulting fractured objects are very low res.

I looked into this and I see that about 2 years ago, the bundled Cell Fracture add-on had a lot more options than what are available now in 2.91. Specially, it appears that there was once a 'Simplify Base Mesh' option in the Cell Fracture setup (along with numerous other options) but they are no longer present in the add-on.

Even though it would appear that the 'Simplify Base Mesh" option has been removed, is it plausible that the add-on is applying this feature during the fracture process?

I would like to avoid Cell Fracture from simplifying my mesh. I am also curious about why the current version of Cell Fracture has fewer options available than it appears to have in previous versions.

Event Timeline

Providing screen shots of before / after Cell Fracturing a high-poly mesh.

Before Fracture

After Fracture

Philipp Oeser (lichtwerk) changed the task status from Needs Triage to Needs Information from User.Wed, Feb 17, 4:40 PM

Not sure if we are talking about

  • Cell Fracture / object_fracture_cell
  • Cell Fracture Crack It / object_fracture_crack

These are two different Addons.
There has been some back and forth in regards to merging them:
rBACf00d4fbe84852e40af281267c06dc21bafb5df49.
rBAC1857eaff3077a0d44b2f50570d7ad12e48c76d05

So just to make sure: doe you have both installed?
Crack It has this Simplify Base Mesh option, so maybe something gets mixed up here?

Cell Fracture / object_fracture_cell

Philipp Oeser (lichtwerk) changed the task status from Needs Information from User to Needs Triage.Thu, Feb 18, 6:34 PM