The Modeling tools are made available so you can try them out and provide feedback to us. They are in an early stage of development and are subject to change in a later release.
Twinmotion offers a collection of modeling tools you can use to optimize and edit the 3D models you import into Twinmotion. Use the tools to edit the shape and structure of meshes, and create new ones by splitting them into parts, mirroring them, or merging them together.
You can use the modeling tools on:
Imported 3D polygonal models.
Sketchfab and Quixel Megascans assets you download from the Twinmotion Library.
Fixed Twinmotion assets you download from the Twinmotion Library.
The Twinmotion library contains fixed and smart assets. You can only use the Twinmotion modeling tools on the fixed assets.
The modeling tools are contained within the Modeling panel and are organized in the following tabs:
| Tab | Description |
|---|---|
Faces | Consists of operations for the following:
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Mirror | Consists of operations for the following:
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Merge | Consists of operations for the following:
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Split | Consists of operations for the following:
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For more information about the options in the tabs, see the Faces, Mirror, Merge, and Split sections below.
Accessing the Modeling Tools
The modeling tools are located in the Modeling panel. To open the Modeling panel, in the footer click Modeling.
The Modeling panel appears on the right-side of the viewport. To enable the modeling tools and start using them select an object in the viewport and click one of the tabs.
Key Concepts and Terminology
Before using the tools, we recommend understanding a few key 3D modeling concepts and the terminology used in the Modeling panel.
Triangles
The objects you download from the Twinmotion Library and the 3D models you import into Twinmotion are converted into a collection of triangular polygons, also known as triangles. Triangles are composed of a vertex set (vertices), edges, and a face.
The vertices represent the coordinates or position of the triangle in 3D space.
The edges are the lines that connect the vertices.
The face is the surface of the triangle and contained within the connected edges.
Meshes
Triangles are connected together to create the basic structure of 3D models, also known as the topology. The mesh maps the surface of the objects to create a three-dimensional representation of them. The mesh is also sometimes referred to as the wireframe.
In Twinmotion you can view the triangles and the 3D mesh of objects by selecting the Show wireframe checkbox in the Faces tab.
Connected Polygon Groups
Triangles that are grouped together are known as connected polygon groups.
Simple 3D models can be composed of only one connected polygon group. More complex 3D models with multiple parts can have multiple connected polygon groups to represent the different parts.
Normals
Faces have two sides and an orientation: one side points inwards, facing the inside of the object, and the other side points outwards, facing the outside. The orientation of a face is defined by the orientation of the normal (or vector) on the face. You can visualize normals as a line that is perpendicular to the face and points either inwards or outward.
The orientation of normals has an impact on many aspects of 3D rendering such as which side of an object a material appears on, surface detail, lighting, and reflections. When you import 3D models into Twinmotion, the orientation of normals sometimes need to be flipped.
With the Twinmotion modeling tools, you can view the orientation of face normals and flip them. Normals that point outwards are represented in blue, and normals that face inwards are red.
Welding
You can merge meshes to create new objects or parts. When you merge meshes, there can be gaps between the triangles which can lead to rendering issues. To correct this, you can weld or connect the vertices of triangles together to create a smooth border and remove the gaps between the triangles.
Mirror Plane
When you mirror an object, a transparent rectangle—known as a mirror plane—appears between the original object and the mirrored object. The mirror plane represents the current position and rotation of the mirrored object.
In Twinmotion, the color of the mirror plane changes according to the selected mirror direction: red (right or left), green (front or back), or blue (top or bottom) These colors are the same as the ones used to represent the X, Y, and Z axes of the gizmo.
Faces
The following table describes the options in the Faces tab.
| Option | Description |
|---|---|
| Selection mode | |
Single face | Selects or deselects one face at a time. |
By material ID | Selects or deselects all faces that have the same material ID. Twinmotion identifies all materials by a name and a set of unique numbers that represent their ID. When you select a face by material ID, all other faces in the object that have the same material ID are also selected. |
Connected group | Selects or deselects all faces in the same connected polygon group. |
All | Selects the faces of all the meshes in the scene. |
Deselect | Deselects any currently selected faces in the scene. |
Invert | Inverts the selection of faces. Selected faces are unselected, and unselected faces are selected. |
| Faces | |
Delete | Deletes selected faces. |
Detach | Detaches selected faces from objects and creates a new object with them. The new object appears as an element in the Scene graph. |
Show wireframe | Shows a see-through wireframe (the mesh and all the faces) on top of objects. |
| Normals | |
Flip normals | Inverts the orientation of normals on selected faces. |
Auto fix normals | Attempts to automatically fix the normals of the mesh based on the current face orientation and face angle threshold between the faces. The same normal orientation is applied to faces that are roughly on the same plane. If specific faces are not selected, all the faces that need to be flipped on a selected object are fixed. |
Show face normal orientation | Shows the orientation of normals on faces. Faces pointing outwards appear blue, and faces pointing inwards appear red. |
Mirror
The following table describes the options in the Mirror tab.
| Option | Description |
|---|---|
Mirror directions | Mirrors objects in the selected direction or orientation according to the selected Mirror plane location and Merge mode. Mirroring refers to duplicating an object or part of an object and creating an exact symmetrical copy of it. Options: Right, Left, Front, Back, Top, Bottom |
Mirror plane location | Determines the X, Y, Z position and rotation of the mirror plane when objects are mirrored, and whether objects are mirrored according to Bounding box, World, or Pivot. Options:
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Merge mode | Specifies the method used to merge mirrored and original objects. Options:
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Weld point on connected parts | When selected, the vertices of original and mirrored triangles are merged if the distance between each vertex and the mirror plane falls within the Weld tolerance value.  |
Weld tolerance | Specifies the minimum distance that the mirror plane and a vertex must be in relation to each other before they are welded. |
Apply button | Applies and saves the mirroring changes. In the Mirror tab, the changes you make are in preview mode only. You must click the Apply button to accept and save the changes. |
Merge
The following table describes the options in the Merge tab.
| Option | Description |
|---|---|
| Actions | |
Merge selected | Combines selected objects in the scene that have overlapping boundaries. |
| Merge mode | |
Weld points | When selected, the vertices of the original and mirrored triangles within the area specified in the Weld tolerance value are joined together.  |
Weld tolerance | Specifies the area within which vertices must be located to be joined together. |
Delete source objects | When selected, the source objects that are merged are deleted and replaced with the new merged object. By default, this option is selected. |
Split
The following table describes the options in the Split tab.
| Option | Description |
|---|---|
Actions | |
Split by material ID | Splits objects into separate parts by material ID. Objects must have more than one material ID. Twinmotion identifies all materials by a name and a set of unique numbers that represent their ID. When you split meshes by material ID, all meshes that have the same material ID are split into separate parts. |
Split by connected group | Splits objects into separate parts based on the connected polygon groups. Objects must have more than one connected polygon group. Separated parts appear as elements in the Scene graph. |
| Split mode | |
Delete source objects | When selected, the source objects that are split are deleted and replaced with the separate parts. By default, this option is selected. |