Spline Combiner Manual


  1. Version Requirements / License / Installation
  2. Overview
  3. Boolean Splines
  4. Shape Cutter
  5. Detect Intersections
  6. Tools rollout
  7. Help/About
  8. Contact/Support

Version Requirements

3dsMax 2012 and higher.
Spline Combiner has been tested succesfully on 3dsMax 2012 to 2023. It should also work properly on future versions. However, if you experience any issue, please report it to contact@splinedynamics.com


With every purchase you get a lifetime license. It’s a node-locked license.
The Regular License lets you use the product in 2 different workstations. It comes with 2 license keys (1 domain per key).
The Corporate License allows you to activate the plugin on up to 10 workstations. It comes with 2 license keys (5 domains per key).
You will get free upgrades for the same major version of the product.


  1. Unzip the content of the .zip file and then drag the “.mzp” file onto one of your viewports in 3ds Max . The plugin automatically installs itself.
  2. A dialog called “Software Activation” pops-up. Enter your license key in the text field. (You received a license key by email when you purchased the product).
  3. If the license key is correct, Spline Cleaner will start.
  4. To add the plugin to a toolbar, go to the Menu > Customize > Customize user interface…
  5. Go to the “Toolbars” tab and pick the category “Spline Dynamics”.
  6. The plugin’s name, “Spline Combiner”, must be listed there. Just drag it onto a toolbar and you’re done!


Spline Combiner is a 3dsMax plugin for simultaneous editing of multiple spline curves, wich lets you perform boolean operations between shapes, cut and break them down into parts and control curve intersections.

It has 3 main modules or rollouts: Boolean Splines, Shape Cutter and Intersection Detection.

Boolean Splines: to combine multiple independent shapes with boolean functions, like in 2D vector softwares, using Union, Subtraction or Intersection methods.

Shape Cutter: to make cookie cuts on shapes and conveniently break down splines into parts.

Detect Intersections: to automatically detect intersections between splines (or self intersections) and add new vertices or place helpers.

The Tools rollout includes 3 handy tools, wich complement the previous ones and help you speed up the process: attach selected, weld vertices and flatten.

At the bottom of the UI, there’s the Help/About rollout, wich contains links to online tutorials and the plugin’s credits.

Boolean Splines

Spline Combiner Boolean Operations between splines This tool lets you combine multiple independent shapes using boolean functions.
The plugin provides 2 different methods for performing boolean operations: Standard Boolean and Overlaping Edges.

The general procedure for both methods is the following:

1. Select all the shapes that will participate in the operation.
2. Choose the method to use: Union, Intersection or Subtraction.
3. If you chose Subtraction, then press the button “Pick operand A” and pick the shape from wich you want to subtract the other shape/s.
4. It is recommendable to leave the checkbox “Close, flatten and make coplanar” checked. This will set your shapes ready for performing a boolean operation satisfactory. (You may want to uncheck it in certain cases)
5. Press MAKE BOOLEAN to complete the action.

Standard Boolean
This is the classic boolean method where you work with 2 or more overlapping shapes to make a union, intersection or subtraction operation between them.
It requires the shapes to be closed, flat and coplanar (laying on the same plane in 3D space) to be successful.

Overlapping Edges
This method lets you combine multiple contiguos shapes (they need to have coincident edges/segments). It works with both open and closed splines.
It requires the shapes to be flat and coplanar, but not necessary closed.
It works by detecting the coincident lines/segments between shapes and performing automatic tasks like deleting, attaching splines or welding vertices where needed.
It provides a Threshold parameter to specify the maximum distance between lines/segments at which they will be considered coincident/overlapped.
A great use of the union/combine  operation in this case, is to create a contour or outline for a set of tightly arranged shapes.

Spline Combiner -boolean splines - overlapping edges

Known issues and exceptions

There are some cases in wich the boolean operation cannot be resolved properly. If you see the result is not what you expected or you get a warning message telling you the plugin could not complete the action, then consider the following options.

  • Spline Combiner boolean functions may not work correctly at unusual scales in 3dsmax (too big or too small sizes). Try to scale up or down your shapes before the operation.
  • If there’s a big difference between the sizes of the shapes you selected (e.g., one shape is less than 10% the size of another), the plugin may failed. You can try resolving the problem by using the Detect Intersections method, wich is more precise, and finish the task manually.
  • Another cause of failure may be when there are too much shapes involved in the action. In this situation, just split the task, performing several boolean operations using less shapes to achieve the same final result.

If you experienced other strange behaviour or you think the tool is not working as it should, please report it to us through this Contact Form.

Shape Cutter

This tool lets you make cookie cuts on closed shapes or conveniently break down splines into parts. Usage:

1. Select all the shapes that will participate in the operation.
2. Press “Pick Cutter Object” and select the shape you will use to cut the other shapes. The cutter shape can have any number of sub-splines, either open or closed.
3. It is recommendable to leave the checkbox “Flatten and make coplanar” checked. This will set your shapes ready to perform this operation satisfactory. (You may want to uncheck it in certain cases)
4. Tick the corresponding checkboxes if you want to “produce open splines” and/or “detach all elements” (These options are explained further in this chapter).
5. Press APPLY CUTTER to complete the action.

If you leave the option Cookie cut for closed shapes on, the cutter object will act as a cookie-cutter on closed shapes, producing closed splines. If you uncheck this option, the plugin just adds vertices at intersections and breaks the splines at those points, producing open splines.
(See the image on the left to understand the difference)

The option Detach all elements, as you can imagine, will leave the resulting splines as subobjects or detach them all to new objects.

Known issues and exceptions

The Shape Cutter tool has the same restrictions and known issues as the Boolean Splines tool. So please look at that previous section for a detailed explanation.

Detect Intersections

This tool can automatically detect intersections between splines (or self intersections) and add new vertices or place helpers at those points.

1. Select all the shapes for wich you want to detect intersections.
2. Choose the options you desire at the UI areas of Intersections, Action and Helpers.

Intersections Area

Here you define what kind of spline intersections you want to find:
a) between different shapes
b) between sub-splines in the same shape
c) self intersections in single splines

We recommend you to mark only the options you need. The more options you select, the heavier are the tasks to process and, therefore, the action will take more time to be completed.

Action Area

Here you choose what do you want to do about the intersections found:
1. Refine. Add new vertices on splines at each intersecting point.
2. Split. Break the splines at those points (resulting in more spline subobjects).
3. None. You should check this option if you only want to place helpers at intersections.

Detach all elements (checkbox): Only available if Split is marked. It detaches all splines as new objects.

Helpers Area

Place helpers (checkbox): If on, the plugin will place one point helper per each intersection point. The helpers are instances, so you can select one and change its properties, and the changes will be reflected in all the instances.
Everytime helpers are created, a new 3dsMax selection group is added. So you can select that specific group of helpers later.

Also at this area, you can change the size and color of the recently created helpers, or delete them.

Tools rollout

Attach Selected

Attaches the selected shapes together.
If the checkbox Optimize for extrusion is on, the plugin does 2 additional actions:
1) it fixes the direction of the local Z axis (extrusion axis) so it is oriented in a proper way for a later extrusion.
2) It welds the shape’s vertices with a tolerance of 0.1 units, to avoid overlapping vertices and close open segments.

Weld Vertices

Lets you weld the vertices of all the selected shapes, using the established Threshold parameter.


To flatten the selected shapes in the desired axis direction (X, Y or Z).
The option Make shapes coplanar, ensures all the selected shapes lie on the same plane.

Help / About rollout

This rollout contains:
a) Links to Spline Combiner online tutorials
b) A button to access the plugin’s License Activation dialog. To activate your plugin’s license and turn off the trial version.
c) The plugin’s version number and credits.

Contact / Support

If you experience any issues using this plugin or need help, please check first the Spline Combiner Forums. Maybe you can find the solution there and save precious time.

For custom support or making suggestions or business proposals, please don’t hesitate to contact us through this Contact Form.

You can also write us directly to contact@splinedynamics.com.

All feedback is greatly appreciated. We will try to answer all your inquiries as soon as possible.

Enjoy Spline Combiner!