There are many features in common between UDK/Unreal3 andUE4 ... features that were carried-over or replicated. There are some incremental improvements, as well as wholesale replacement of features.
So i thought i would give my top three things that seasoned UDK users might get thrown off by.
The First and perhaps most noticeable change is Scale. unreal and UDK operate on in UU or Unreal Units;
UDK- 1UU = 2cm
UE4-1UU is now equal to 1cm.
This allows maps/levels to be sized more accurately sized, and helps eliminate confusion with modelers when setting the size of props; The gotcha here is that the maximum size of the world is cut down, in UDK it is 10.48km x 10.48km; In UE4 it is 5.24km x 5.24km.
Item two, Assets have been totally revised in UE4; In UDK a collection assets were stored in a package; these packages got large quickly and made for a challenge to Source control. Now in Unreal Engine 4, all assets, regardless of kind(e.g. Texture, material, static mesh, Etc...) are store individually as .uasset files.
Maps in UDK are .udk files and in UE4 they are .umap files.
The Third change i would like to talk about is the importing static meshes and annimations. the actorx, .PSK and .PSA importing process is now defunct, and FBX files are the standard(and only way) to import meshes, animations and skeletons.
Bonus change; The UCX_MESHNAME collision mesh importing functions as it did in UDK with one change, it now allows for multiple collisions meshes per mesh using UCX_MESHNAME_xx, where xx is the number of the collision mesh (e.g. 00, 01, 02)
Now, there are far more things to know, when transitioning from UDK/Unreal3 to Unreal Enginge 4... far to many to list here; however you can find an extensive list on the unreal wiki here
If you are Like us, you enjoy walking on the Bleeding edge of new software; You love digging into new tools, and unlocking it's mysteries.... well, if you are like us, you too may be at a TOTAL LOSS as to why the people at Epic chose to use a 2 year old version of the FBX tools.
What is FBX?
FBX is, in the opinion of many, the best way to import and export 3d files... not just for UE4 for many uses.
It came from a program called FilmBoX, developed by Kaydara in the 90's ... which was later bought by Autodesk, and became MotionBuilder... as part of developing MotionBuilder, Autodesk has added an array of great features to the FBX file format, including things like stored animations, and LOD groups, Super useful for game content. in the last couple of years, it has become the standard way to get Assets into motion and game engines... it is a staple of the Tall ship workflow.
Again if you are like me, you are using the newest software, So Maya 2014, that is where the problem comes in... Maya 2014 uses the 2014 FBX tools... and the 2015 tool-set is available to developers(but not yet released); Whereas, UE4 uses the 2013 FBX tools.
So, What's the REAL problem?
Aside from a warning when importing, which can be disabled, there is no obvious signs that there is a problem.
what we have seen, is that the lightmaps don't layout on the meshes properly on LOD-Group based models... I suspect that it is the way the UV sets are packaged in the different FBX SDKs. there are a few issues with importing collision also(using the "UCX_MODELNAME" naming Convention) To be fair, we have only seen an issue when importing a LOD group with 2 or more UV sets; and i'm not sure how common this is.
end result; Lights and materials don't layout on the Meshes quite as you expect... not a desired result
to be clear, this will only fix import issues directly caused by mismatching fbx tools, and the UE4 error popup warning you there is a mismatch; you have to have a valid Maya file or it doesn't matter what you do...
And I fix this, How?
The quickest and most simple solution, if you have to use maya 2014, is to create an export preset.
In the File menu, click on the square Options box off to the side of Export Selection
(Export all and Export selection will both work for this; however, they Maya stores these settings separately, so you may need to repeat these steps if you use both Export methods... we only use export selection when making FBXs...)
THis Brings up the Export Options.
on this dialog we want to make sure that the 'FBX_Export' is the selected, then simply click the 'Edit preset...' button(shown below)
this brings up the 'Edit export preset' dialog; This is where you set all of the options that determine what and how maya content gets exported.
There are a metric tonne of options and many of them are beyond the scope this post; Visit the Official Documentation site for a more in-depth look at the export presets.
if, you are editing an existing preset, make note of it's name in the Current Preset dropdown.
Now you can set the options however you like... Go crazy have fun... when you are done with that, under the section called 'Advanced Options' expand the 'FBX File Format' section and click the version dropdow, the version UE4 expects is the 'FBX 2013' version.
It is recommended that you leave the type binary, as Unreal in the past has had issues using it.
Save, Save, And... wait for it... SAVE. you don't want to have to constantly change these settings so save the preset, via the 'Save Preset' button at the bottom.
this will ask you for a name. Here we are using the name 'Unreal 4' ; if you are replacing one that already exists you must type in the name exactly.
CLicking close take you back to the first dialog, the 'Eport Selection Options' Dialog
click 'Export Selection' and the Save dialog comes up.
Note this is the default Maya Save Dialog, if you are using the OS Native or other option, it will look different.
all you have to do is verify that the current preset is set to what we saveed it as.
In this Image you can see that the preset clearly says "Unreal 4" so we are good to go.
This is a set and forget option, the preset stays the same until you change it... so from here on out you should be going like gangbusters.
Can you suggest a similar how-to? Let us know in the Comments below.
Tall Ship Team
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