Hi Metin, also here's an overview of the most significant new stuff for v4:

New in version 4:

Major rewrite to a cross platform code base.

64-bit builds for both Windows and Mac.

Native Mac build, compatible with new operating systems.

Multi-core processing for opening CAD files - Loading objects from 3DM, STEP, IGES, and SAT files will now use multiple CPU cores to process objects being loaded resulting in a major speed increase.

Display engine updated to make use of modern GPUs with lots of VRAM - display data is now cached in the GPU's VRAM which results in faster redraw speed for large files.

Polygon Sub-d surface to NURBS conversion method, available on the side pane under SubD > Create > From file. This a llows you to open an .obj file that contains a sub-d polygon cage and have it converted to a high quality NURBS objects in MoI. This enables a hybrid workflow where you can make a base surface for an object in a sub-d modeling program and then bring it into MoI to continue working on it with CAD tools.

Annotation objects - add dimensions and text to your model to use for 2D documentation. These are added by 7 new commands in the Dim tab on the side pane: The DimHorizontal command creates a linear dimension going in the x-axis direction of the construction plane: The DimVertical command creates a linear dimension going in the y-axis direction of the construction plane: The DimAligned command creates a linear dimension going in any direction on the construction plan All 3 of the linear dimension commands have a "From object" button in their command options which you can trigger to take the start and end point of a curve as the first 2 points of the dimension. The DimRadius command creates a radial dimension on a circle or arc curve: The DimAngle command creates an angular dimension on the construction plane. There is a "From lines" button in its command options which will allow you to select 2 line objects instead of picking points. The Leader command creates a leader object which is a text label with an arrow. The AnnotationText command creates an annotation text object which is a text box by itself, no arrows

Added dimension property preset system for controlling initial properties of newly drawn dimensions. Accessed under Options > Dimensions. The properties set for the "Default" preset are stored in moi.ini and so if you want the same settings used in all projects you can set that one. You can also create additional presets for project-specific settings. Any presets after "Default" are stored in .3dm files. When you draw a dimension there is now a "Preset:" option which you can set to control which preset will be used.

New Detailed object properties dialog. Gives additional information about the object type and allows for calculating the length of curves, the surface area or volume of a surface or solid and adjust properties for annotation objects.

DXF import - support reading layers and import/export of dimension entities. Import of TEXT, MTEXT, LEADER, and DIMENSION (linear, angular, radius/diameter sub types) is now supported. MoI will export dimensions to MTEXT, LEADER, and DIMENSION enties.

Added circumference field in addition to radius/diameter for circle drawing commands.

Add length field to ArcCenter command.

Implement sizing of the scene browser by dragging on its edge.

Update FBX export - FBX version, object names, and materials. Add option for which FBX version to use under Options dialog > Import/Export > FBX options > FBX version. Object names are now written to the FBX files instead of only generic "object1", "object2", ... names and styles are now written as materials in the FBX export. Writing materials can be disabled in moi.ini under [FBX Export] WriteMaterials=n

Settings for page size are now available in PDF/AI exports.

Handle file write errors - an error dialog will show now on file write failures like if the system ran out of disk space or permission denied.

Numerous bug fixes.

There is a more detailed list of all V4 beta release notes gathered here:
https://moi3d.com/wiki/V4Beta .

- Michael