preparing a 30 scene for datasmith -...

Preparing a 30 Scene fo r Datasmith Tne Datasmith Importer for u nreal Engine 4 (UE4) supports Autoctesk 3DS Max using an exporter plugin and a variety of CAD file types

natively. In almost all cases, you snould not need to adjust your content and Oatasmith snould "just worl<" when you import it into UE4.

Each of the supported OCCs creates and manages its assets in ways that aren't alWays going to align With a real-time engine. The

sections of this guide detail some general guidelines that you can reference when creating your projects or provides some insight into

how your content is translated to Unreal through Datasmith.

For a comprehensive list of supported software and file types, see the Datasmith Supported Software and File Types page.

General Content Guidelines

Below are some general guidelines for creating your content in your software package and some additional topics you should be aware

of when importing content into Unreal using Oatasmith.

Geometry

Level of Deta il (LODI

Currently, level of detail (LOO) meshes are not imported or generated at import for your scene geometry. This process can be automated

using the Pytnon sclipting plugin in unreal Engine 4.

Manually creating LOOs using Unreal Engine 4's own mesh reduction system can be achieved by following the steps in the Setting up

Automatic LOO Generation.

Collision Primit ives

Currently, collision primitiVes are not imported or generated at import for your scene geometry. This process can be automated using the

Python scripting plugin in Unreal Engine 4.

Manually adding collision to your scene and Static Meshes can t>e achieved in one of two ways:

• Use a Blocking Volume to act as collision for a section of your scene in the level.

• Set up collision per-Static Mesh using Simple Collision shapes or Convex shapes that more closely matell your geometries shape.

UV Coordinates for Lightma p UVs in UE4

Lightmaps are a uniquely unwrapped UV where every part of the model has its own representatiVe space. II is used during a light build to

generate a texture that stores light and dark information for the Actor in the scene.

Below is the process that Datasmith uses to generate a lightmap UV:

1. Datasmith content is imported ·as-is". It preserves the UV Channels that object in 3DS Max may nave. Depending on now the

object was set up, it can have up to 99 UV Channels.

2. Datasmith generates an additional UV cnannel that does an auto-unwrap. It ensures that UV charts are not unwrapped property.

3. The UV channel created in step 2 is used to generate the lightmap UV that will be used when you build lighting for the scene. The

lightmap is appropriately padded and packed based on the Static Mesh Lightmap settings used during the Datasmith Import

process.

The Datasmith import process will always generate two unique UV channels that are used to create a functional lightmap UV. These UV

channels Will be added to the existing list of UV Channels that are viewable through the Static Mesh Editor toolbar.

Textures and Materials

When textures and materials are imported using Datasmith, their properties and Characteristics are translated to ones that Unreal Engine

4 can use. The following are supported texture inputs that can be converted to ones used by UE4's Material Editor:

• Diffuse/Base Color

• Specular Value or Texture

• Roughness Value

• Opacity Value and Mask

• Normal Map

• Displacement and Tessellation

• Refraction

Depending on the complexity of the material being imported, it will be set up accordingly where possible. For example, if you nave a

glass material in your software package, the one created in UE4 will be set up to use a Translucent blend mode in UE4. If the material is

using an opacity mask, UE4 will set up one tnat is using a Masked blend mode when it assigns and connects the texture inputs.

For additional information, see the Material Blend Mode page.

Be aware that not all software packages translate their materials the same way, so some materials may require extra set up in

Unreal Engine 4 or may not be supported at all when importing from your Datasmith scene.

Lights

Unreal Engine 4 is a real time renderer, so tnere are some features that are supported in offline rendering software that is not or cannot

be supported.

Unreal Engine 4 is a real time renderer, unlike many software packages tnat use offline rendering. Th is means that some features

supported for offline rendering are not yet supported or cannot be supported due to limitations. When lights are imported using Datasmith

for Unreal Engine 4, they are converted using features and properties tnat currently align With UE4's.

Datasmith attempts to translate the folloWing features during import:

• Position

• Orientation

• Shape

• Size

• Intensity

• Units Lamp Color

• Filter Color

Unfortunately, features aren't always translated and sometimes you'll need to make adjustments in UE4. For additional information about

using lights in Unreal, see tne Lighting Basics page.

Naming Convent ions

Unreal Engine 4 naming for assets only accepts alphanumeric characters and no spacing. Spaces will be replaced with an underscore

and cnaracters tnat are not supported by unreal are dropped. For some applications, like with 3DS Max, tne object name Will only be

reflected in the World Outliner for the asset in your level but the name of tne asset stored in the Content Browser will be the unique

reference ID used by your application to the object. This is commonly used under the hood when applications support object naming

where multiple objects can be named the same thing but are different assets. Unreal Engine 4 supports this for Actors in your Level

through the World Outliner as well.

Scene Hierarchy

When your Datasmith scene is imported and placed in the active level, tne naming and ParenVChild hierarchy are preserved if hierarcny

and metadata export is supported from your software package. In the UE4 World Outliner, the Actor hierarchy will be preserved under a

root Actor with the name of tne Datasmith Scene file that was imported and appended by _Root.

Seject 0 1iplay Edit ·;; Vi'o·ld Out 1rsPr

SCENE ROOT

~-- CAMERA

r·· ~LANEOOI

j ~----~ M_STATUE

j ~--·· FSPOTOOI

j l--··FSPOTOO2

L- SPOTOOI

In this example, the scene hierarchy is displayed in 3DS Max and how it is set up in UE4's World Outliner. The scene root in the World

Outliner takes on the name of the CAD or unreal Datasmith file that is imported. In this case, the hierarchy is preserved under

Statue _Lighting_ Root.

Autodesk 30S Max Scene Gu idelines

AutooesK 3DS Max uses a custom Datasmith Exporter plugin that outputs an unreal Datasmith (•.UDATASMITH) file. Some functionality

presented here is unique to how we output that information from 3DS Max and tnen import it into UE4.

Toe following examples apply to Unreal Datasmit h (•.UDATASMITH) files generated by the Autodesk 3DS Max Exporter plug in

that are imported into Unreal Engine 4.

Geometry

Pivot Points

3DS Max allows you to set custom pivot points for objects in your scene, regardless of them being instanced. unreal Engine 4 does not

currently support custom piVot points for instances.

To support custom pivot points for instances, Datasmith exports custom pivot information as a sub-component. Unreal uses this

information to create a sub-component for the corresponeling Actors in the level. In the example below, Teapot002's pivot is the root

component anel Teapot002_Pivot is the instanceel mesh set as a chilel of the root that is acting as the custom pivot point.

Inst ances with Custom Pivot Points and Non-Unifo rm Scaling

Instances of an object in 30S Max that use a custom pivot point anel have been non-uniformly scaleel are a special case that unreal

Engine 4 cannot support. Attempting to export content that exhibits these characteristics using Datasmith will generate a warning in the

30S Max Output warnings Winelow Cluring export:

INVALID TRANSFORMS

Some objects have customized pivots and nonuniform scales. Those combinations are not supported by Unreal and will produce incorrect results.

It is recommended to use the Resetl Xf orm Utility on those objects:

To solve the issue, use the 30S Max utility for Reset XForm on those objects:

• Utifities

More ...

Perspective Maid,

Colapse

Color Clipboard

Measure

Motion CaptJSe

MAXScript

Flight Studio (c)

• Reset Transform

Reset Selected

Lights

3DS Max supports a variety of light types for its scenes, such as Standard, Photometric, V-Ray, and Corona. Tile intent of Datasmith is to

support the following characteristics of those lights:

• Position , Orientation, Shape, and Size.

• Intensity, Units Lamp Color, and Filter Color

• Render Shape Visibility

• Instancing

However, unreal Engine 4 does not currently support the following light Characteristics:

• Instanced Lights

• Area Ug his

Lights are imported With With their ParenVChild Actors and Components are added in the level to Actors to handle the visible light shape.

The Child Actor is the Light Actor, Where you can further adjust the properties of the light

Light shapes can t>e selected in the Shape/Area Shadows section of light properties of 3DS Max which translate to a drop-down

selection t>ox for Light Shape in UE4.

• Shape/Area Shadows

Emit light from (Shape)

Rectangle

length:

Width:

Rendemg

100.0

300.0

.,, light Shape VlSble in Rendering

Shadow Samples: 1..4 •

3DS Max

.11111 Appearance

Uglit Shape

[> Dimensions

[> Col or

Intensity

X 1000 .,, Y 300.0 ....

Unreal Enaine 4

Tne visibility of the light Shape can be enabled and disabled by using tile Actor Hidden In Game clled< box found in the Details panel

of UE4.

~ Rendermg

~ Editor Billboard Scale -

Light Color and Intensity

During the conversion of lights to UE4, tile folloWing characteristics nave been preseJVed:

• Intensity

• Kelvin Temperature

• Filter Color

• Light Type (IES Profiles, Spotlig his, etc.}

• • • • t e e e -

- • - ~~ ••••

30S Max Unreal Engine 4

Top: Point Lights with /ES Profiles and scaled KeMn Temperatures; Middle: Point Lights with /ES Profiles and scaled light intensity;

Bottom: Spot Lights with Filter Color.

There may be some minor differences between lighting in your 3DS Max scene versus your Unreal Engine 4 scene. You may have

to make some adjustments to your lights inside of UE4 to get similar results.

Known Issues

• Since lignt instancing is not supported, using two Ugnt Actors adds clutter to tne scene.

o In a future release, tne idea is to combine tnose two Light Actors as a unique Blueprint Object.

• Support for some V-Ray light snapes are not property converted. For example, Vertical Cylinder, spneroid , and Custom Mesn

lignts.

• Standard lights are unitless and allow for custom attenuation parameters tnat are not supported by UE4. Tnese lights will require

some manual adjustment in UE4

• Emissive snapes for lights Will not contribute to Ugntmass calculations in UE4 when building lighting. It is purely a visual effect at

tn is time.

Text ures and Materials

30S Max UV Channels vs Unreal UV Channels

In 3DS Max, you are allowed to nave up to 99 UV cnannel associated Witn an object. Unreal Engine 4 only allOws for eight UV cnannels

to exist. wnen Datasmitn content is exported to unreal Engine 4, tne Datasmitn export plugin will consolidate tne UV cnannels found and

create an array tnat contains up to eight UV channels. It does tnis by sl<ipping any blank slots use a UV channel but contain no UV

charts.

For example, the 3DS Max object below has five UV channels in its modifier list. Each one of these UVs nas a number associated Witn it

between O and 99 stored on the object wnicn represent tne UV channel slot being used. In Unreal, only five UV channels (plus the two

lightmap UV channels) will be imported and generated, producing seven UV channels overall.

+ !C Vemces

Modfier list

Reser Camera

UV Channel 0

UV Channel 1

UV Channel 2

UV Channel 3

UV Channel 4

UV Channel 5

UV Channel &

Below is a breakdown of tne same example, with explanations for the UV channels imported from 3DS Max and tne ones generated for

Ughtmap UVs.

30S Max UV Channel

2

3

10

99

Resulting Unreal UV Channel

0

2

3

4

5

Notes

The UV channel 1 in 30S Max is assigned to UV channel O in Unreal.

The UV channel 2 in 30S Max is assigned to UV channel 1 in Unreal.




UV channel 5 in Unreal is generated during import to create an automatic unwrap of the geometry contained in

the Oatasmith scene. It is the basis for the lightmap UV generation used by UV channel 6.

6 UV channel 6 in Unreal is generated based on UV channel 5 to correctly pad and pack the UV charts based on

the Oatasmith Import Options used for the Static Mesh Lightmap Resolution values.

Materials Best Practices

Datasmith attempts to export 3DS Max materials With a good level of fidelity an<! recreate them in u nreal Engine 4. However, there are

limrtations With regar<ls to the complexity of the material that can be exported. Because of th is, you must consicler the following When

looking to bring materials from 3DS Max into UE4:

• 3DS Max supports multiple shading models for materials, such as V-Ray, Corona, Arnol<l, Mental Ray, an<! more.

o Each shading model is a separate piece of software that eacn have their own unique features an<! are inconsistent from one

another.

• To support an arbitrary number of these materia l graphs in Unreal Engine 4 woul<l require that eacn Material or Map plugin from

3DS Max also exists in Unreal.

o To support that init iative, a large part of 3DS Max functionality for Unreal woul<l have to be adde<l, which is not planne<l.

Since unreal cannot support the variety of these shading models for the MaterialS you create in 30S Max, below are some examples of

what workS best When exporting your materia ls to Unreal Engine 4.

Materials that are relatively ·simple· will translate better than complex shader graphs.

• M<4>•S Billnap

• MapOJ Botmop

Cliek image for fuJI size.

Complex material graphs will not likely have issues converting or nee<l a<l<litional clean up in UE4'sMaterial E<lnor. An example of a

complex material would be one tllat uses many <lifferent shaders neste<l in one another.

Cliek image for fuJI size.

Autodesk Materials do not translate in Datasmittl. These are materials that are usually imported from Autooesk Revn.

Naming Convent ions

Stat ic Mesh Asset Name

When naming your assets in your software application an<l then importing tllem into Unreal, you may fin<l that tile name of your assets is

not the same. There are a couple of reasons that tllis coukl be:

• Unreal Assets must have unique names

• Name and path locations are limite<l to 256 characters

• Non-Alphanumeric characters are not supported, inclu<ling ones from different languages

For example, in 30S Max, object names are not enforce<l to be unique, can have an arbrtrary length, an<l use arbitrary characters. This is

important to note When supporting reimport worl<flows, an<l searcn and replace. There needs to be a persistent han<lle to objects an<l the

object name is not something that should be relie<l on. As a result, with 30S Max, the nO<le han<lle is used, which is a unique object

identifier provided by the 30S Max SOK as a way to identify entnies that are unique.

30S Node ID vs Object Name

Imported Static Meshes in UE4 are name<l according to tile internal "nooe ID" handle used to reference an object for tile following

reasons:

• Object Names are not enforced to be unique and can nave arbitrary lengths and cnaracters from different languages.

• Unreal assets must nave unique names only include alphanumeric characters and are limited to a file patn name of 256 characters.

• To support reimport wort<flows for Datasmit11, a persistent nandle to objects is neected. Object names in 3DS Max cannot be reflect

on in tnis instance.

Tne World Outliner in unreal Engine (that lists all your Actors in tne currently loaded level) uses tne Object Name from 3DS Max for easy

reference.

Select Display Edit Customize

X l!a ri] Name (Sorted Ascending Age)

~ O, SpotOOl.Target

r.1 O • I CameraOO 1

E.I o • Plane001

i!J o, Fspot002

~ o, FspotOOl •, SpotOOl

0 e SM_Statue

·-~ World Outliner -,> Levels

Label Type

0 A•;J Untnled (Editor) ,'/::, 1 I::: 0 .. • Statue_Scene_Root :. :: ~::,I

0 t._,..- CameraOOl :11-1fJC, ,:1c1t.

0 f, , FspotOOl :: 1:, ::,~L ,· 0 f, , Fspot002 :: 1:, ::,~L ,· 0 r) PlaneOOl :: ~ C1 ~I:: I.'.- 1-1i

® Q SM_Statue Actor SpotOO l

7 actors (1 selected) <!> v ,ew Options~

However, when you select tne Actor in tne Level or from tne World Outliner, the Details panel displays a reference to tne Static Mesh

Actor that uses the node ID handle from 30S Max to identify the asset.

1 ~arf,;

0:: Blueprint/Add Script

"'Transform

L,XJtl:>r ,,..

"'Materials

Cliek image tor fuJI size.

Using the node ID handles to identify the asset in UE4 makes the most sense since it is a unique object identifier proVided by tne 3DS

Max SOK. It identifies all entities tnat are unique in your scene, even if they are given tne same Object Name.

To quickly locate an asset in your scene in the Content Browser, use tne magnifying glass next to any asset in referenced in the

Details panel. The Content Browser will show the asset in its folder location in the Content Browser.

Click image tor full size.

In 3DS Max, you can locate a corresponding object by using MaxScript to get the same node with the following command:

Maxops.getnodebyhandle [number)

CAD Scenes

The following sections apply to natively supported CAD files imported using Datasmith for Unreal Engine 4. These sections contain

general information and lips that you shoukl be aware of when developing and planning your CAD scenes for use in UE4.

Geomet ry

Geom etry Tesselation

For applications that use a mathematical representation of its assets versus using polygonal geometry, during import, a polygonal mesh

will be created based on tne settings used for Geometry & Tessellation. These values determine how complex the mesh that is created

will be when represented in unreal Engine 4.

Data smith Import Options

Import File Hypospray Vl O stp

Import To /Game/

_. Include

Geometry ~

Materials & Textures t!'J lights ~

Cameras ~

.o1111 Static Mesh Options

Min lightmap Resolution

Max lightmap Resolution

_. Geometry & Tessellation Options

Chord Tolerance

Max Edge Length

NOfmal Tolerance

Version O 17 (?J

0 2 cm ....

00cm ....

111111

• \,,;OOra 101erance: 1 ne 111a.x1r11u111 uIst.c:u1ce uetwee11 a ye11eIa teu uIa.ny1e a.110 me 01191110.1 su11a.c..:e. ~111a 11e1 va1ues 111t.::1ease ma11y1e

counts.

• Max Edge Length: The maximum length of an edge in the triangles generated from a surface. Smaller values increase triangle

counts.

• Normal Tolerance: The maximum angle between adjacent triangles generated from a surface. Smaller values increase triangle

counts.

Due to the potential complexity of CAD files and having to generate a mesh during import, you may notice that import limes can

increase or take a while based on the values used for the Geometry & Tessellation Options.

Lights

For CAD programs that support Lights in their scenes, these will attempt to be imported and retain their properties where possible. This

may be improved for future releases.

Texture and Materia ls

Currently, texture import from CAD files is limited or not supported but is planned to be added in a future release.

Materials and Colors

Materials imported that are different colors in a source CAD file are imported as a Material Instance and reference a Master (or Parent)

Material in UE4.

UV Coordinates

Due to the way CAD files are created and how they must be translated to UE4, UVs for materials and textures is limited. Currently, the

only uvs are ones generated for the Lightmap uv in Unreal Engine 4. The first UV is flattens out all the geometry and the second UV

(that becomes your Lightmap UV for your Static Mesh in UE4) re-packs all tile UV islands so that tnere are no overlapping faces.

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