Researching Fog in
UDK
As I mentioned previously I am shifting
my workflow pipe line of pre production from Maya only to Maya through to UDK.
This means I need to ensure I take time to learn any special techniques for UDK
as a part of my pre production work. After all, that’s the idea of BA7.
Following on from my Maya fog research
I now need to understand how to build it in engine. The engine im using is UDK
so I figured the best place to start would be in the UDK manual. Here I found
some really well written explanations of the different types of fogs that can
be created in UDK as well as the correct terminologies for the workflow.
Fog Volume
The first type of fog that I am going
to be studying and creating within UDK is called FOG VOLUME. It essentially consists of three
separate functions that can alter its appearance, they are: DENSITY which controls the fall off of the fog,
a MESH which contains the density function and
a MATERIAL that displays the colour of the fog.
Fog volumes form a set within the fog
height actors in UDK which I will go into separately. The difference between
fog volumes and fog height is that volumes can be bound by a mesh, display
multiple density functions and be customised.
Before I start showing you my progress
so far this evening I must admit that I am very new to UDK at the moment. My
knowledge goes about as far as exporting an FBX asset from Maya into UDK,
bringing across my textures and materials and then adding a very basic
collision mesh. I began this study thinking this wouldn’t be too hard to have a
go at but I found myself getting easily frustrated as I cant quite get the fog
to appear how I want it to yet. However, this is only my first study and I plan
to talk to my tutors to get a bit more knowledge with the capabilities of the
fog volumes in UDK.
Setting Up Fog
Volumes: Automatic Setup
As I didn’t really know what I was
doing at first I opened up a static mesh from the CONTENT BROWSER because I
thought, from the tutorials I was following, that I could apply the fog volume
to the overall mesh and tailor it to sort of “float” atop the mesh. I was wrong. Either way, this is what I
did first.
Open a STATIC MESH from the CONTENT BROWSER in UDK, UDK has a library full of pre
built and textured static meshes that
you can use to flesh out your level.
I soon realised that it wasn’t this
particular static mesh I needed to apply the fog volume too but another static
mesh that would take control and visually display the fog volumes attributes.
Still confused, I opened up the sphere I thought I was supposed to use from the
content browser static meshes' which was called “FogVolumeSphere”…kinda thought
this was definitely the right thing to use….I was wrong :’)
As you can see, I was given a sharp
sphere made of fog sure, but it wasn’t the look I was going for!
(unfortunately)
This fog wasn’t near anything I was
expecting or wanting in my head so I had to move on. I then built a STATIC SPHERICAL MESH from the CONTENT BROWSER…the correct non fog volume ready one.
The next step was to go back to the CONTENT BROSWER and select the ACTOR CLASSES tab at the top. I then EXPANDED FOG and LEFT CLICK DRAG &
DROPPED FogVolumeConstantDensityInfo into the UDK scene (that’s what the
little green lizard head thing represents…)
The tutorial I was following (foundHERE)
stated that I needed to basically attach the STATIC MESH to the FogVolumeConstantDensityInfo in order
for the FOG VOLUME to
visually change the SPHERE into FOG.
I decided that a sphere wasn’t going to
work very well because I wanted the fog to seemingly float across the floor.
That is when I repeated the initial steps…STATIC MESH (CUBE this
time) > SELECT FogVolumeConstantDensityInfo
FROM ACTOR CLASSES > APPLY
STATIC MESH TO ACTOR ATTRIBUTES TO CREATE CUBED FOG.
This is where I learnt how to use the
VIEWPORT (similar viewport to Maya) in UDK whereby I could select the STATIC
FLOOR MESH (rocks) and RESIZE them so that they were bigger than the FOG
VOLUME. I was then also able to learn the tool whereby I can manually
manipulate the geometry within UDK which enabled me to lower the FOG VOLUME so
that it appeared to sit on top of the floor.
I was then able to use the FogVolumeConstantDensityInfo
attributes to edit the FOG VOLUMES DENSITY.
And here is the final outcome :D
I am pretty pleased with myself for
learning this with the aid of the tutorials and help from friends I was able to
learn a new techniques that will help my pre production work flow and pipe line
work towards BA8. I am sad that I only got this far tonight, there are other
forms of fog volumes that I want to try but now that I have this basic method
down I really hope the others are a little more straight forward. Something I
want to discuss with my tutors is if there is a way to make the fog drop off at
the edges as currently this looks far too box ish with harsh edges that I do
not want. Id also like to see if there are any ways to create an animated
rolling fog effect similar to the one I created in Maya because I simply cant
find any tutorials online that are beginner friendly! Still, I am happy with
this step forward in terms of progress, a step forward is always better than a
step backwards ;D
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