ZBrush Decimation and Export 1 — Questions and Answers
Question 1: What is the primary purpose of Decimation Master in ZBrush?
- To generate game-ready quad topology via ZRemesher
- To reduce the polygon count of a high-poly ZBrush mesh while preserving visual detail for rendering or 3D printing (Correct answer)
- To merge all SubTools into a single decimated mesh for export
- To apply a subdivision level reduction across the entire ZTool
Correct answer: To reduce the polygon count of a high-poly ZBrush mesh while preserving visual detail for rendering or 3D printing
Decimation Master reduces a high-poly ZBrush mesh (often millions of polygons) to a much lower polygon count using optimized triangle reduction that preserves the visual surface detail, making it suitable for rendering, 3D printing, or import into DCC applications.
ZBrush sculpts routinely reach 10 to 50 million polygons — far too heavy for most downstream use. Decimation Master analyzes surface curvature and concentrates triangles where detail is highest (eyes, wrinkles) while aggressively reducing flat areas. The result can be 95% smaller while appearing visually identical at normal viewing distances. It is the standard prep step before exporting to a 3D printer, Keyshot, or as a high-poly bake source.
Question 2: What does the 'Preprocess Current' button in Decimation Master do?
- Applies one round of ZRemesher to reduce polygon count before decimation
- Analyzes the active SubTool's surface to calculate optimal decimation weights for a subsequent Decimate Current operation (Correct answer)
- Removes all subdivision levels above level 1 to prepare for export
- Runs a topology analysis and assigns polygroups based on surface curvature
Correct answer: Analyzes the active SubTool's surface to calculate optimal decimation weights for a subsequent Decimate Current operation
Preprocess Current analyzes the active SubTool's surface detail and stores an internal curvature map that guides where triangles should be concentrated during the subsequent Decimate Current step.
Decimation Master is a two-step process: Preprocess (analysis) then Decimate (reduction). Preprocessing can take significant time on very high-poly meshes as it computes a per-vertex importance weight based on curvature. Running Decimate without preprocessing uses a default flat weight, producing inferior results. Preprocessing only needs to be done once per mesh unless the geometry changes significantly.
Question 3: What is the difference between OBJ and GoZ export in ZBrush?
- OBJ exports only the active SubTool; GoZ exports all visible SubTools simultaneously with topology, UVs, maps, and a direct bridge to the target DCC (Correct answer)
- OBJ includes rig data; GoZ exports geometry only
- GoZ is a ZBrush-specific binary format; OBJ is for 3D printing only
- There is no practical difference — both produce the same file output
Correct answer: OBJ exports only the active SubTool; GoZ exports all visible SubTools simultaneously with topology, UVs, maps, and a direct bridge to the target DCC
OBJ is a static geometry export of the active SubTool. GoZ is a live bridge that transfers all visible SubTools — with UVs, polypainting as texture maps, and displacement — directly into a supported DCC with two-way update capability.
GoZ installs a plugin in the target DCC. When you click GoZ in ZBrush, it exports all visible SubTools and automatically imports them into the linked DCC with proper naming and map assignments. Clicking GoZ again after sculpting updates the DCC mesh without re-importing. OBJ has no round-trip — it is a single snapshot.
Question 4: What file format should you choose when exporting a ZBrush sculpt for 3D printing that requires watertight geometry?
- OBJ
- STL (Correct answer)
- FBX
- ABC (Alembic)
Correct answer: STL
STL (STereoLithography) is the standard file format for 3D printing, accepted by virtually all slicing software. ZBrush's export produces watertight STL files suitable for FDM and resin printing.
ZBrush's Export palette supports STL export directly. For printing, the mesh must be watertight (no holes, no inverted normals) — Dynamesh is often used to ensure this before export, as it produces fully closed volumes. STL does not support color or UVs. For full-color printing, OBJ+MTL or 3MF are used instead. STL remains the default for single-material prints.
Question 5: How does ZBrush's Decimation Master differ from ZRemesher in its output and use case?
- Decimation Master produces optimized triangles preserving visual detail; ZRemesher produces clean quad topology for animation and rigging (Correct answer)
- Decimation Master produces quads; ZRemesher produces triangles
- Both produce identical triangle meshes; they differ only in processing speed
- Decimation Master adds subdivision levels; ZRemesher reduces them
Correct answer: Decimation Master produces optimized triangles preserving visual detail; ZRemesher produces clean quad topology for animation and rigging
Decimation Master outputs optimized triangles that preserve visual appearance at minimum polygon count — ideal for rendering and 3D printing. ZRemesher outputs clean quad topology suitable for animation, rigging, and subdivision — ideal for production pipelines.
These are complementary, not competing tools. Decimation Master is right for 3D printing exports, game high-poly bake sources, and realtime viewport models. ZRemesher is right for rigged game characters, subdivision surface base meshes, and animation-ready topology. A typical pipeline uses ZRemesher for the game low-poly and Decimation Master for the high-poly bake source.
Question 6: What does enabling 'Mrg' (Merge) in ZBrush's OBJ export settings do?
- Merges all subdivision levels into a single polygon mesh
- Merges all visible SubTools into one OBJ file during export
- Combines UV islands into a single atlas before export
- Welds duplicate border vertices to create a watertight mesh (Correct answer)
Correct answer: Welds duplicate border vertices to create a watertight mesh
The Mrg option in ZBrush's OBJ export settings welds duplicate vertices at shared borders, producing a unified, watertight mesh rather than a mesh with duplicate border vertices — essential for applications that require closed manifold geometry.
Without Mrg, OBJ export can produce a mesh with duplicate vertices along shared borders between polygroups or originally separate pieces. This creates open edges that cause issues in polygon modelers, simulation tools, and 3D printing slicers. Enabling Mrg welds those pairs of coincident vertices, closing the gaps.
ZBrush Decimation and Export 1
What is the primary purpose of Decimation Master in ZBrush?