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Help Document

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MaxShell is a MaxScript for Autodesk 3ds Max. MaxShell creates an inner shell which can be used to hollow out the models.

It is useful for reducing the volume of the model in case the model is 3D printed. Less volume means less material, faster printing and less cost.

It can also be useful where the usual shell modifier does not work well, such as for organic models.

Or it can be used to create vases and anything that needs to be hollow.

Supported versions of 3ds Max are 2014-2019.

Get MaxShell !

How to use?

  1. Pick the model.
  2. Place the seed inside it.
  3. Click the Build Shell button.
  4. Click the Flip and Attach button.

The model is hollowed now.


Here is a description of what the settings do -

Watch the video for a tutorial and more detailed description.

Pick the Model : Click to select the model which needs to be hollowed out. The model will lose all modifiers and the transform will be reset.

Seed Size: Change the size of intial inner shell. Seed should be small enough to be places completely inside the thickest part of the model, but should not be too small. It should not interset the surface and should not be place very near to the surface. Twice the distance of wall thickness is a good clearance between the seed and model surface.

Seed Segments: Number of segments of geosphere which is used as a seed for the inner shell. More segments will produce more triangles. Should not be too low or too high.

Thickness: The required wall thickness of the model after hollowing. Recommended to add about 1% extra thickness, just in case.

Expand: Number of times the seed will expand to fill in the inner volume. If it cannot expand more because the volume is filled up, the process stops and skips the extra expansions. But if the expand is set to a low number, the seed may stop before it can fill up the volume. So if you have a big model, set it to higher number.

Iterations: This is the number of times the script attempts to move the shell's vertices towards the target object's surface. These happen at every expansion step.

Step Size: The distance the shell's vertices move in every iteration (as mentioned above). Lower values give finer results but take more time. Very high values can cause the shell to pass through your model prematurely.

Triangle Area: Controls how big the triangles in the inner shell's mesh are. Smaller values gives you a dense and finer mesh. Bigger values means faster execution and a low poly mesh.

Redraw Frequency: Number of times the viewports are redrawn during execution.

Flip Shell: When checked the script will flip the normals of the shell so that they face inwards.

Attach: When checked the script will attach the shell to the model, completing the hollowing process.

Auto UV and Material: When checked, the shell will get an (almost) point UV map and will get the material of the target model.

Build Shell: Starts the shell building process. You can try pressing Escape key to stop it, it may take some time to stop. When it finishes normally, a "Shell Created" message appears in mini maxscript listener.

Flip and Attach: Does what it says. Sometimes you may want to inspect the shell before attaching and make some changes etc, so keep the above mentioned checboxes unchecked. You can undo this operation. The one done automatically cannot be undone.

Thin Wall Checker

It is a bonus add on utility which checks for wall thickness. Useful for models that need to be of a specific thickness for 3D printing.

Wall Thickness: Set the thickness below which the wall is treated as too thin.

Check: Starts the check. You need to select some polys in the model before you click this. Select the areas which you suspect are too thin. If you select the whole model, it can take a long time to execute. The result is a selection of polys where the thickness is less than that set above.

Select Thin Walls Again: Does that if you deselected the result for some reason. Or you can make amends in the model and use the last selection as a starting point for re-checking the thin walls.


Note that you may need to make one or more holes in the model to drain out the supporting materials inside the cavity of the 3D printed model.

The dimensions of the holes are usually specified by the printer manufacturer.

Some printers may treat the model as solid when there are no holes in it.

Introduction to MaxShell and Tutorial:

Note : A demo max file has been provided with the script for testing and troubleshooting etc. (Download MaxShellDemo001.max)

Video link:


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Oormi Creations

© March 2018