To create a thick or curvy edit of a Novabeast avatar in VRChat, the most effective process involves using Blender for mesh modification and Unity for parameter implementation. Specifically, you should use the Shape Key method in Blender to expand the hips, thighs, and glutes, ensuring the modification is toggleable and does not break existing animations. After modifying the mesh, you must adjust the Weight Painting to prevent leg clipping and configure PhysBones in Unity to add realistic movement to the new volume.

Understanding the Novabeast Base for Customization

The Novabeast, created by Kittomatic, has become one of the most beloved avatar bases in the VRChat community. Its stylized, anthropomorphic design features a robust silhouette that lends itself perfectly to "thick" or curvy edits. However, modifying a professional-grade model requires more than just scaling bone sizes; it requires an understanding of 3D mesh topology and how VRChat handles deformations through its SDK.

When users talk about a "thick edit," they are generally referring to increasing the volume of the lower body—specifically the thighs, hips, and glutes—while maintaining or slimming the waist to create a more pronounced silhouette. Because the Novabeast is already well-rigged, performing these edits requires careful attention to the underlying bone structure to ensure that the avatar still functions correctly in Full Body Tracking (FBT).

Preparing Your Project and Respecting the ToS

Before touching any vertices, ensure you have the original Novabeast files. This model is a paid asset, and most "thick edits" shared online are either personal modifications or paid add-ons. You must own the base avatar to legally use or create an edit.

  1. Required Software: Download Blender (version 3.5 or higher is recommended) and the Unity Editor (specifically the version currently supported by the VRChat Creator Companion).
  2. Importing the FBX: Locate the Novabeast.fbx file in your project folder. When importing into Blender, ensure "Manual Orientation" is checked and "Apply Transform" is enabled to keep the scales consistent.
  3. Check the Terms of Service: Kittomatic’s license generally allows for private edits and public versions, provided the original credits remain and you do not redistribute the raw files to those who do not own them.

Method 1: The Shape Key Approach (Recommended)

The Shape Key (also known as Blendshapes) method is the professional standard for avatar edits. Instead of permanently moving the vertices, you create a "slider" that tells the vertices where to move when the slider is active. This allows you to have a "standard" Novabeast and a "thick" Novabeast on the same model.

Creating the Shape Key Basis

Open Blender and select the body mesh of the Novabeast. Navigate to the Data Properties tab (the green triangle icon). You will see a list called Shape Keys.

  • Click the + button once to create the "Basis." This represents the model in its original, unedited state.
  • Click the + button again to create a new key. Rename this key to something descriptive, like Body_Thick or Thigh_Expander.

Sculpting the Curves

With the new Shape Key selected and its value set to 1.00, switch from Object Mode to Sculpt Mode.

  • Symmetry Settings: In the top right corner of the viewport, enable X-Axis Symmetry. This ensures that every modification you make to the left leg is perfectly mirrored on the right leg.
  • The Inflate Brush: Select the Inflate brush. Set the strength to a low value (around 0.2). Gently brush over the outer thighs and the glutes. This brush adds volume by pushing vertices away from each other along their normals.
  • The Grab Brush: Use the Grab brush to pull the hips outward and the glutes backward. This helps define the silhouette more aggressively than the Inflate brush alone.
  • The Smooth Brush: Hold Shift while sculpting to activate the Smooth brush. Use this frequently. If the topology (the grid of lines on the model) becomes too stretched or jagged, the textures will look distorted in VRChat.

Balancing the Silhouette

A common mistake in thick edits is focusing only on the thighs. For a natural look, you should also slightly expand the calves and the lower abdomen to maintain a cohesive flow. Once you are satisfied, switch back to Object Mode and slide the Shape Key value from 0 to 1 to see the transition.

Method 2: Permanent Mesh Editing for Extreme Proportions

If you are looking for a permanent change that exceeds what a Shape Key can cleanly handle, or if you want to change the "default" look of the FBX permanently, you will use Edit Mode.

  1. Proportional Editing: In Edit Mode, select a vertex in the center of the thigh. Press O to enable Proportional Editing.
  2. Scaling: Press S to scale. You will see a circle around your cursor; scroll your mouse wheel to adjust the size of this circle. This "falloff" ensures that when you scale up the thigh, the surrounding waist and knee areas move gradually rather than creating a sharp, ugly edge.
  3. Correcting the Crotch Area: When making the thighs significantly thicker, the inner thighs will often merge or "clip." You must manually move the inner thigh vertices slightly outward to maintain a gap, or at least a clean seam, so that the walking animations don't look like the legs are melting into each other.

Advanced Weight Painting Optimization

This is the most technical part of a thick edit. The Novabeast's mesh is "bound" to its bones via Weight Painting. When you move the vertices further away from the bone (by making them thicker), the original weights might cause the mesh to stretch strangely when the leg bends.

Fixing Thigh Deformation

Switch to Weight Paint Mode and select the LeftUpperLeg bone from the Vertex Groups list.

  • The colors represent how much the bone moves that part of the mesh (Red = 100%, Blue = 0%).
  • If you have added significant volume to the glutes, ensure that the Hips bone and the UpperLeg bones have a smooth gradient transition. If the transition is too sharp, the butt will "collapse" when the avatar sits down.
  • Use the Blur Tool in the Weight Paint panel to soften the edges between the hip and the thigh weights.

Testing the Bend

In Blender's Pose Mode, rotate the leg bones to a sitting position. If you see the mesh "poking through" or folding like a piece of paper, go back to Weight Painting and adjust the values until the bend looks like organic flesh.

Exporting to Unity

Once your Blender work is done:

  1. Select the mesh and the armature.
  2. Go to File > Export > FBX.
  3. In the export settings, under Object Types, select Armature and Mesh.
  4. Under the Transform tab, set "Apply Scalings" to FBX All.
  5. Under Armature, uncheck "Add Leaf Bones."

Import this new file into your Unity project, replacing the original Novabeast FBX in your scene.

Implementing PhysBones for "Thick" Dynamics

A thick edit only feels "real" in VRChat if it has the appropriate weight and movement. VRChat’s PhysBones system allows you to simulate fat or muscle movement.

Setting Up Glute and Thigh Jiggle

The Novabeast base often comes with chest and tail PhysBones, but for a thick edit, you might need to add them to the "butt" bones if your edit includes them, or apply them to the mesh itself using specific vertex transforms.

  • Component: Add the VRC PhysBone component to the bone corresponding to the area you want to jiggle.
  • Pull and Spring: For a "heavier" feel, keep the Pull value relatively high (0.2 - 0.3) and the Spring value moderate. This prevents the mesh from vibrating uncontrollably.
  • Immobile Type: Set this to World (Under Parent) to ensure the jiggle reacts to the avatar's movement through space.
  • Collision: If you want the thighs to "collide" or have hand-interaction, set the Radius of the PhysBone collision shape to match the new, thicker mesh volume.

The "Squish" Factor

In the PhysBone settings, there is a parameter for Max Squish. For thick edits, setting a small amount of squish allows the mesh to compress slightly when touched or when the legs press against each other, which significantly increases the immersion of the model.

Texture Repair and UV Consideration

When you inflate a mesh in Blender, the UV map (which tells the texture where to sit) stays the same, but the physical space it covers increases. This causes "texture stretching."

  1. UV Smoothing: In Blender's UV Editing tab, you can select the stretched areas (like the thighs) and use the Minimize Stretch tool. However, this may require you to bake new textures.
  2. Substance Painter: The best way to fix a thick Novabeast's look is to bring the edited mesh into Substance Painter. By repainting the fur patterns or gradients on the new, larger surface area, you eliminate any blurring or distortion caused by the mesh expansion.
  3. Detail Masks: Use a detail mask in your Unity shader (like Poiyomi or Liltoon) to add a fine fur grain. This grain stays consistent regardless of how much the base mesh is stretched, hiding any low-resolution texture areas on the thighs.

Handling Clothing and Accessories

A thicker Novabeast will not fit into standard Novabeast clothes (like the default hoodie or tactical gear) because the body will clip through the fabric.

  • The "Shrink" Blendshape: Most high-quality Novabeast clothing assets come with "Shrink" or "Delete" blendshapes for the body. You can use these to hide the skin under the clothes.
  • Editing the Clothes: If you want the clothes to fit the "thick" shape, you must bring the clothing mesh into Blender and apply the exact same Shape Key modifications to the clothes that you applied to the body.
  • Lattice Modifier: A quick trick in Blender is to use a Lattice Modifier that encompasses both the body and the clothes. When you deform the Lattice to make the body thicker, the clothes will deform perfectly along with it.

Using SkinEdit for Faster Modifications

For those who find Blender intimidating, the SkinEdit Novabeast tool by Markcreator is a powerful alternative.

  • How it Works: It is a Unity-based editor that provides sliders for various body parts.
  • Capabilities: It includes "Thick" and "Curvy" presets that automatically adjust the mesh and update the PhysBones for you.
  • Limitation: While much easier, it offers less artistic control than a manual Blender sculpt. It is ideal for users who want a high-quality result without spending hours weight painting.

Conclusion

Creating a "thick" Novabeast edit is a rewarding way to personalize your VRChat experience. By utilizing Shape Keys in Blender, you maintain the versatility of the original model while achieving a customized silhouette. The key to a successful edit lies in the details: smooth transitions in the Sculpt Mode, careful Weight Painting to handle movement, and the implementation of PhysBones in Unity to provide the necessary physical feedback. Whether you do it manually for total control or use tools like SkinEdit for efficiency, always remember to test your avatar in various poses—sitting, crouching, and dancing—to ensure your new proportions look as good in motion as they do in the mirror.

FAQ

Why does my Novabeast look "crunchy" after I made it thicker?

This is usually caused by not using the Smooth Brush enough during the sculpting phase. If the vertices are unevenly spaced, the lighting in Unity will create weird shadows. Go back to Blender and use the Smooth brush on the affected areas.

Can I make a thick edit for the Quest version of Novabeast?

Yes, but you must be mindful of the Polygon Count. While making a model thicker doesn't necessarily add polygons, extreme edits might require more complex weight painting which can occasionally impact performance on mobile hardware. Also, remember that Quest does not support the same advanced shaders that PC does, so texture stretching will be more visible.

How do I stop my legs from clipping into each other when I walk?

In your VRChat Avatar Descriptor, you can adjust the Locomotion animations, but the real fix is in Blender. Move the inner thigh vertices slightly outward or ensure your weight painting on the UpperLeg bones is not pulling the opposite leg's mesh.

Do I need to redo the Face Tracking if I edit the body?

No. Face Tracking is handled by Shape Keys on the head mesh. As long as you only modify the body mesh and do not delete the head's Shape Keys or change the bone hierarchy of the neck/head, your face tracking will remain fully functional.

Will my thick edit work with VRChat's IK 2.0?

Yes. VRChat's IK (Inverse Kinematics) system calculates bone positions. Since a thick edit usually only moves vertices and not the bones themselves, the IK will function normally. However, you may need to adjust the "Avatar Scale" in the VRChat menu to match your new height or width for better floor alignment.