Introduction
Splines are one of the most useful modeling tools in 3ds Max.
For archviz, they are helpful for floor plans, wall outlines, openings, furniture details, trims, countertops, geometric patterns, and simple architectural shapes.
This tutorial covers the basic spline tools and the decisions that matter when you are building clean production scenes.
Open the Shape Tools
Go to the Create panel on the right side of the screen.
Click the second icon, which is the Shapes category.
Make sure the drop-down menu is set to Splines.
From here, you can create spline primitives such as:
- Rectangle
- Circle
- NGon
- Line
These are 2D shapes at first, but they can later become 3D geometry.
Start with a Rectangle
Choose Rectangle.
Click and drag in the viewport to set the size.
This is useful for simple architectural shapes such as:
- Wall outlines
- Floor plan areas
- Countertops
- Panels
- Furniture parts
Watch the View Orientation
The spline aligns to the view where you create it.
If you draw a rectangle in the Front view, it stands upright like a wall.
If you draw it in the Top view, it lies flat on the ground.
For architectural floor plans, start in the Top view. This keeps the base flat and avoids tilted geometry later.
Tip: When tracing a floor plan, use the Top view so your spline stays aligned to the ground plane.
Add Radius to Rectangle Corners
With the rectangle selected, go to the Modify panel.
Find the rectangle parameters and adjust the Corner Radius.
If the radius is set to 0, the corners are perfectly sharp.
This can look too digital because real objects rarely have perfectly sharp 90-degree edges.
A small radius helps the edge catch light better.
This is useful for:
- Furniture legs
- Countertops
- Cabinet details
- Modern wall panels
- Architectural trim
Good practice: Even when an object should look sharp, use a very small radius when possible. It makes the object render more realistically.
Use Circles for Round Forms
The Circle spline works in a similar way to the rectangle.
Click and drag in the viewport to create it.
Circles are useful for:
- Columns
- Round tables
- Circular ceiling details
- Round floor patterns
- Decorative features
Again, pay attention to the viewport where you draw the spline. A circle drawn in the Top view will sit flat. A circle drawn in the Front view will stand vertically.
Use NGon for Geometric Shapes
The NGon spline is useful when you need clean geometric shapes with exact symmetry.
It can create polygons with different numbers of sides.
For example:
| Sides | Result |
|---|---|
| 3 | Triangle |
| 6 | Hexagon |
| 8 | Octagon |
This is useful for:
- Geometric floor tiles
- Wall patterns
- Decorative screens
- Nuts and bolts
- Repeating architectural details
The main benefit is precision. You get mathematical symmetry without trying to draw the shape by hand.
Understand Start New Shape
The Start New Shape option controls how 3ds Max organizes new splines.
When Start New Shape is enabled, every new spline becomes its own separate object.
This is useful when you want each object to stay independent.
When Start New Shape is disabled, new splines are added into the same spline object.
This is useful when one spline needs multiple parts, such as:
- A wall outline with window openings
- A shape with interior cutouts
- A circular border with a hole inside
- Elevation details with openings
3ds Max can understand the relationship between the outer shape and the inner shape. The inner spline can act like negative space when the shape is converted into geometry.
Tip: Disable Start New Shape when you want to create holes or cutouts inside the same spline object.
Draw Custom Shapes with the Line Tool
The Line tool gives you more freedom than the basic primitives.
It lets you draw your own shape point by point.
Single Click for Sharp Corners
If you single click as you draw, 3ds Max creates corner points.
This produces sharp, angular lines.
Use this for:
- Walls
- Floor plan tracing
- Rectangular outlines
- Hard architectural edges
Click and Drag for Curves
If you click and drag, 3ds Max creates a Bezier point.
This adds handles that control a smooth curve.
Use this for:
- Curved walls
- Organic paths
- Rounded furniture shapes
- Decorative elements
Use Shift for Clean Angles
While drawing with the Line tool, hold Shift.
This constrains the line to clean angles such as:
- 90 degrees
- 45 degrees
This is very useful when tracing floor plans because it helps keep walls straight and aligned.
Production tip: Use Shift when drawing architectural walls. Small angle errors can create problems later when extruding or aligning other objects.
Finish or Close the Line
When you are done drawing, right-click to exit the Line tool.
If you want to close the spline loop, click back on the first yellow vertex.
A closed spline is important when you want to create filled shapes or extrude solid geometry.
Examples include:
- Wall profiles
- Slabs
- Panels
- Countertops
- Openings
Edit Splines in Sub-Object Mode
To edit a spline after creating it, select the spline and go to the Modify panel.
Open the sub-object levels and choose Vertex.
Now you can select individual points and edit how they behave.
Right-click a selected vertex to see the vertex options.
Choose the Right Vertex Type
Different vertex types create different shapes.
Corner
A Corner vertex creates a sharp angle.
Use it for rigid architectural forms such as:
- Wall corners
- Room outlines
- Rectangular furniture parts
- Hard edges
Bezier
A Bezier vertex creates a smooth curve with handles.
Move the handles to control the curve.
If the handles are far from the vertex, the curve becomes wider.
If the handles are close to the vertex, the curve becomes tighter.
Bezier Corner
A Bezier Corner gives you separate control on each side of the vertex.
This is useful when you need one side of the curve to behave differently from the other.
Use it for more controlled organic shapes or custom curved details.
Refine Corners with Chamfer and Fillet
You can refine sharp spline corners using Chamfer or Fillet.
Select a sharp corner vertex first.
Chamfer
Chamfer cuts the corner with a flat angled segment.
This creates a straight beveled corner.
Use it for:
- Flat cut corners
- Simple architectural details
- Hard-surface design elements
Fillet
Fillet rounds the corner.
Drag to control the amount of rounding.
This is useful for realistic edges on:
- Countertops
- Furniture parts
- Trim profiles
- Rounded architectural details
Tip: Fillet is a fast way to remove overly sharp spline corners before turning the shape into 3D geometry.
Fix Unconnected Vertices
Sometimes two vertices look connected, but they are actually separate.
This can break the model when you try to extrude or create clean geometry.
Use this workflow:
- Select the vertices.
- Use Fuse to place them on top of each other.
- Use Weld to permanently join them.
Fuse only stacks the points together.
Weld actually connects them.
Important: If your spline does not extrude correctly, check for open or unwelded vertices.
Convert Splines into 3D Geometry
Splines are 2D shapes. To use them as real objects in your scene, you often need to give them thickness or height.
The classic way is to apply the Extrude modifier.
Select the spline, go to the modifier list, and add Extrude.
Small Extrude Amount
A small amount, such as 10 cm, can create a thin plate.
Use this for:
- Panels
- Thin slabs
- Decorative pieces
- Simple trim elements
Large Extrude Amount
A larger amount, such as 300 cm, can create a wall height.
Use this for:
- Basic walls
- Massing models
- Simple room layouts
- Early architectural blocking
This is a quick way to turn a floor plan outline into simple 3D geometry.
Know When Extrude Is Limited
Extrude is great for simple depth and height.
But it is limited for more complex detailing.
For molding frames or detailed profiles, other modifiers such as Sweep or Bevel are better options.
These are useful when you need a spline to follow a profile or create more advanced architectural details.
Practical Archviz Workflow
For beginner archviz work, a simple spline workflow can look like this:
- Use the Top view for floor plan shapes.
- Draw clean rectangles, circles, NGons, or lines.
- Use Shift to keep walls and edges aligned.
- Close the spline when you need a filled shape.
- Edit vertices in the Modify panel.
- Use Fillet or a small radius to soften sharp edges.
- Use Fuse and Weld to fix broken points.
- Add Extrude to create simple 3D forms.
This workflow is simple, but it can be used often in production.
Summary
Splines help you create clean 2D shapes that can become architectural geometry.
Key tools to remember:
- Rectangle for simple flat or vertical shapes.
- Circle for columns and round forms.
- NGon for accurate geometric patterns.
- Line for custom outlines and floor plan tracing.
- Corner Radius for softer, more realistic edges.
- Shift for clean 45-degree and 90-degree lines.
- Fillet for rounded corners.
- Chamfer for flat cut corners.
- Fuse and Weld for fixing disconnected points.
- Extrude for turning splines into 3D geometry.
Conclusion
Spline modeling is a basic skill, but it is very important for archviz.
Once you understand orientation, clean vertices, closed shapes, and simple extrusion, you can build many architectural elements quickly.
Start with simple shapes, keep your splines clean, and use small rounded edges where they help the render catch light. This will make your models easier to manage and more realistic in production.
