SubSpline Manual


    1. Version Requirements / License / Installation
    2. SubSpline Overview
    3. Main Panel
    4. Select Subobjects section
    5. Set ID section
    6. ID’s Order section
    7. Tools
    8. Help/About
    9. Contact/Support

Version Requirements

3dsMax 2012 and higher.
SubSpline 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


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 2 license keys by email when you purchased the product).
  3. If the license key is correct, Spline Refiner 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 (“SubSpline”) must be listed there. Just drag it onto a toolbar and you’re done!

SubSpline Overview

SubSpline is an Advanced Subobject Selector & Material IDs Editor for spline shapes in Autodesk 3dsMax.

This powerful plugin will help you edit your shapes way faster, by providing you with smart and efficient tools for selecting vertices, segments and spline curves.

Also, if you need to manipulate the material IDs in your splines, either by curve or segment, there’s a set of comprehensive tools for this porpose.

Some tools in this plugin work only in subobject level (like the ones in Select Subobjects section), while others can work both at base or subobject level.

SubSpline was ment to work in parallel with 3dsMax Editable Spline tools. You can switch between the different subobject levels directly from the corresponding icons at the plugin’s interface. In the same way, when you change the spline subobject level in 3dsMax, the plugin’s UI is also updated.

If you frequently work with spline curves or you use iToo Software RailClone® plugin, you will find SubSpline really useful.

Main Panel

The main pannel (at the top) contains general commands and remains always visible. The other sections (rollouts) have specific tools and can be scrolled up or down to navigate them.

Expose Vertex Numbers (check button)
Show/hide the vertex numbers for the currently selected shapes in the active viewport. The little color picker at the top-right (light blue square) lets you change the font color for the numbers.

Expose Material IDs (check button)
Show/hide the material ID of every segment in every spline of the selected shapes. It shows the ID number next to each segment. The little color picker on the right (green square) lest you change the font color.

Undo Last Action (green arrow icon)
Goes back to the state previous to the last action performed with this plugin. (This is a custom undo implementation, independent from 3dsMax’s undo command)

Restore Original IDs
Revert all the changes made with this plugin to the material IDs of the selected shapes.

Vertex / Segment / Spline (icon buttons)
These 3 check buttons are clones of the ones in 3dsMax Editable Spline parameters and have the same function: enable or disable the corresponding subobject level edition.
When active, all the controls in Select Subobjects section become enable and ready to operate.
You can hold CTRL key while pressing one of these buttons to convert between different subobject selection types, like in 3dsMax Editable Poly.

Regarding subobject selections and material IDs:
For vertex selections, a material ID is considered selected when both vertices at the ends of a segment with that material ID are selected.
For spline selections, the plugin generally considers as valid  those splines that have a single material ID along the whole spline . However, it will accept as input splines with mixed material IDs, depending the operation.

Select Subobjects section

The goal of the tools in this section is to simplify and automate complex subobject selection tasks. The entire section is disabled by default. When you press one of the three subobject level buttons in the Main section (vertex/segment/spline icons), the section is enabled.

All the tools in this area work at the 3 subobject levels, with some slight variations depending the case.

Shrink / Grow (buttons)
Expand or reduce the current selection along the spline/s.
In the case of spline subobject level, it will consider neighbours (for selection) the splines with the closest indices to the current minimun and maximum indices.

Offset Left/Right (< | > buttons)
Move the current selection one place (vertex, segment or spline).
In the case of spline subobject level, it will consider neighbours (for selection) the splines with the closest indices to the current minimun and maximum indices.

Invert (button): Invert the current selection.

Select Random / Dot Selection / Select by Angle (grouped functions)
The tools in this area work in a particular way.
If the option Affect whole is checked: if there’s no subobject selected, the function will apply to all splines in the current shape. Otherwise, it will apply only to splines with one or more elements selected.
If Affect selected is checked: it will apply to the currently selected elements only.

Select Random (button + spinner)
Make a random selection of subobjects (vertices, segments or splines) according to the percentage set in the spinner.

Dot Selection (button + spinner)
Select one element (vertex/segment/spline) every n consecutive elements. The n value is set at the spinner.

By Angle (button + 2 spinners)
Select vertices by angle. You can set min. and max. angles accepted. (Only available for vertex subobject level)

Select By ID (area)
Here are different tools to select subobject elements by their material IDs.

Select ID Range (button + 2 spinners)
With this tool you can select elements with a specific material ID or whose ID is within the range specified by the min. and max. values (spinners). The little ‘L’ button at the right locks both spinners with the same value, to set a single ID value instead of a range.

Select Similar (button)
Select elements with the same material ID/s as the currently selected elements.
In the case of spline subobject level, it will only add to selection the splines that have a single material ID along the whole spline. Splines with mixed IDs will be ignored.

Select Random ID (button)
Pick one of the existing material IDs in the current shape and then select all those elements (vertex, segments or splines) with that ID.

Set ID section

Here you just set a material ID for the current selected shape/s or subobject selection.
There’s a spinner to set any value or 24 numbered buttons to make it quick.


ID’s Order section

The tools in this section can alter the order of the existing material IDs or change them according to certain rules. They work both on selected shapes or subobject selection level.

Copy/Paste IDs (icon buttons)
Copy and paste sequences of material IDs between splines.
It works both within splines of the same object or between different shapes, either selecting sub-objects or at base object level.
When you copy a sequence of IDs, it is added to the list of ID Patterns at Set Pattern tool. So you can use that sequence as a repeatable pattern too.

Offset IDs (< | > buttons)
Move the material IDs, for the current shapes or subobject selection, one place along the spline/s.

Reverse IDs (button)
Reverse the order of the material IDs in the selected shapes or subobject selection.

Set Pattern (dropdown list)
Assign a predefined sequence of material IDs (pattern) to selected shape/s or subobject selection, repeating the pattern along splines.
First select the pattern you desire and then press the little OK button.

Randomize Material IDs (area)
With these tools, you can mess up the existing material IDs (use existing option) or set a range of IDs to distribute randomly along the current selected shapes or subobject selection (set range option). When this last option is checked, the 2 spinners for setting the min. and max. ID values become enabled.


Reverse Spline (button)
Reverse the vertex numbering for all splines in selected shapes or subobject selection.

Flatten (X/Y/Z option + button)
Flatten the vertices in the selected shapes or subobject selection in the given axis.

Select Shapes with Same IDs (button)
This function will find and select all shapes in scene that have one or more of the same material IDs as the current selected shapes.
If you check the option Identical ID sequence, then it will look for those shapes that have exactly the same material IDs, distributed in the same way.

Help / About section

This section includes links to SubSpline Online Tutorials and to this manual.

The About area shows the credits for this plugin.

Contact / Support

For customer 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

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


Enjoy SubSpline!