On the General panel of the Preference Settings dialog, you set options for the user interface and for interactivity.
To set and toggle spinner snap:
Do one of the following:
Either method open the Preferences dialog to the General panel. The two controls for spinner snap are in the Spinners group on this panel.
Enter a value in the Snap field.
Turn on Use Snap and click OK.
When you exit the dialog, spinner snap is on.
As you work, use the Spinner Snap Toggle button to toggle the use of this setting.
To set the Undo level:
Choose Customize menu > Customization > Preferences > Preference Settings dialog > General panel.
In the Scene Undo group, change the value of Levels.
The higher the value of Undo Levels, the more system resources are required. The default value is 20.

Sets the number of operations you can undo.
Sets one coordinate system and transform center for Move, Rotate, and Scale on the Main toolbar. The coordinate system displayed in the coordinate dropdown list, and the transform center selected from the Use Center flyout, are used for all transforms.
Normally, each transform switches to the coordinate system and transform center used the last time the transform was active.
When on, loads plug-ins on demand, as they are needed.
Enables the automatic creation of a Multi/Sub-Object material when you assign a material to a selection of face sub-objects in an editable object. Default=on.
When on, the assigned material becomes part of the new Multi/Sub-Object material, and is assigned to the face selection. When off, the assigned material is assigned to the entire object.
See also Drag and Drop Sub-Object Material Assignment.
When on, the direction that you drag a selection area determines whether it is a window or crossing selection. This works for any selection area (rectangle, circle, fence, or lasso).
You can select which direction causes a window selection and which causes a crossing selection in the Scene Selection group. When you drag a window selection, the selection region is displayed with a solid line; when you drag a crossing selection, the selection region is displayed with dashed lines.
Sets the size of the brush used by Paint Selection Region.
Sets the number of decimal places displayed in a spinner edit field. Range= 0–10 (where 0 is no decimal places).
Sets the click increment and decrement values for all of the spinners in 3ds Max.
Toggles spinner snap on and off.
Limits cursor wrapping to an area close to the spinner when you drag to adjust spinner value.
The number of pixels in a rollout that should be scrollable in the command panel before the rollout is shifted into a separate command panel column.
This option is applicable only when the command panel displays multiple columns.
Earlier versions of 3ds Max used a less accurate method of computing vertex normals. To use the method from versions R1 to R4 of 3ds Max, for compatible display of early scene files, turn on this checkbox.
These options choose how to display and render Normal Bump maps in Nitrous viewports and Quicksilver renderings.
The Normal Bump Mode choice does not affect how Render to Texture bakes normal maps.
3ds Max Mode (The default.) Choose this for compatibility with normal maps baked by the Render to Texture tool.
In this mode, the vertex tangent and binormal (bitangent) are perpendicular to the face normal. The face normal is always perpendicular to the triangle face. During pixel shading, the tangent and binormal interpolated from triangle vertices are used in the normal bump calculation.
Maya Mode Choose this for compatibility with normal maps baked by Autodesk Maya.
In this mode, the vertex tangent and binormal are perpendicular to the vertex normal. Vertex normals take their smoothing group into account. During pixel shading, the tangent and binormal interpolated from triangle vertices are orthogonalized against the normal before the normal bump calculation.
DirectX Mode Choose this for compatibility with the DirectX SDK.
In this mode, the vertex tangent and binormal are perpendicular to the vertex normal. During pixel shading, the tangent and binormal interpolated from triangle vertices are used in the normal bump calculation.
For more information, see the 3ds Max SDK Programmer's Guide > 3ds Max SDK Features > Rendering > Texture Maps > Bump Mapping > Tangents And Bitangents Generation section.
Mikk-T Choose this this option if you want to render or bake normal maps to be compatible with Mikk-T in 3dsMax.
Calculate bitangent per pixel Enable this option when rendering to sync with another application from which the normal map was baked, or when baking to sync with another application where the baked normal map will be used.
When on, and not at a sub-object level, this function displays a tooltip when the cursor pauses over a non-selected object in the viewport.
When on, certain Editable Poly settings use the caddy interface, as described in Editable Poly Settings. When off, the settings use a standard dialog interface.
Starts the Media Player automatically at the end of a Make Preview.
Displays the mouse cursor as full-viewport cross hairs, vertical and horizontal lines extending the full extent of the active viewport.
Each movement of the mouse is redrawn, so the cross hairs are relatively slow. If you want to create a keyboard shortcut, find Cross Hair Cursor toggle in Customize menu > Customize User Interface > Keyboard panel and specify the keys to use for the shortcut. To change the color of the cross-hairs cursor, go to Customize menu > Customize User Interface > Colors panel > Viewports > Cross Hair Cursor and use the color selector to change the cursor color.
Toggles the topology dependence warning. This warning appears when you choose to edit a modifier or the base object at the bottom of the modifier stack of an object with modifiers and sub-object selections. The warning occurs because this action can affect the object topology adversely. You can also turn off the warning on the warning dialog. Default=on.
Toggles the stack collapse warning, which appears if you choose to collapse the modifier stack. You can also turn off the warning on the warning dialog. Default=on.
Restores panels and toolbars to the positions they were in the last time you used 3ds Max. Turn off this switch to restore panels to the state they were in before turning on this option.
Toggles between large and small toolbar buttons.
Ensures that text buttons are displayed horizontally.
If you create a vertical custom toolbar that uses text rather than image buttons, you can use this option to display either horizontal or vertical text.
Specifies the maximum width of text buttons.
To use this feature, turn on the Horizontal Text In Vertical Toolbar switch, turn on this option, and then set a maximum display size for the text button in pixels. For custom vertical toolbars with text buttons, this option limits the size of the text display.
Sets the pause, in milliseconds, between the mouse click and the flyout popping up from the button. Increase this setting only if you need an extra-long delay. Don't decrease the setting much or you might not be able to execute button commands before the flyout takes over.
Choose the default color selector, or a third-party plug-in color selector in the list. The color selector you choose here is used throughout 3ds Max whenever you specify a color.
Select a size for the scrollbars: Small, Medium, or Large. Selecting a larger scrollbar is useful if you have trouble with the default Small size scrollbar, which can occur with 4k monitors. The default is Small.
When on, 3ds Max sets rendering, motion blur, display, and advanced lighting properties for all new objects to By Layer.
When on and you create a light, 3ds Max gets its Object Properties > Renderable setting from the properties of the active layer.
When you unhide or unfreeze an object on a hidden or frozen layer, this choice determines whether the command affects the object or its layer.
Controls whether real-world texture coordinates are active or if the legacy method of applying texture coordinates is in use. When off, texture-coordinate behavior reverts to the legacy method and texture tile values have a default value of 1, and Real-World Map Size for primitives is off. Default = off.
When Use Real-World Texture Coordinates is on, the Use Real-World Scale (for 2D maps) and Real-World Map Size options are also on. Real-World Map Size is available for objects such as primitives and modifiers such as UVW Map.
Restores all preferences to their original factory settings. The existing settings are backed up before reverting. You must close all instances of 3ds Max and restart the program for the changes to take effect.