Setting Up Your SketchUp Model
If you've done any 3D Modeling for OOTP before, you're probably familiar that faces in SketchUp have two sides - front and back, which are shown as white and gray, respectively. In order to properly bake textures with Blender, make sure that every face is showing the front. So when in Monochrome view mode, every face should appear white:
Additionally, you'll want to compartmentalize the model as much as possible by enclosing things inside named components. Each component will be baked separately, so the more components you have, the more detail you'll be able to get. Do not nest components. You can have multiple instances of the same component, but I find that adds unnecessary complexity to the baking process for minimal gain. The exception to this is stadium lighting. While it's irrelevant for the "daytime" bake, it works better for the way Blender handles light emission for each light source to be its own component. It will add steps to the baking process, but it's not terrible.
There are going to be two types of faces that you will want to avoid baking - crowds and "live" scoreboards. Since those can be replaced by OOTP, baking them is not only unnecessary but actually causes problems for the game engine. I would recommend putting those in a "do_not_bake" component to keep things organized.
There are other components that are perfectly fine to bake 9and in , but you won't want them to react to ambient lighting - think of things like LED ribbons, backlit advertisements, that sort of thing. I suggest putting those into components with a "lit_" prefix, so "lit_advertisements" or "lit_led_ribbon", etc. The baking process is a tiny bit different for those, and I'll detail the differences below.
Blender Pre-Requisites
By default, Blender can't read SketchUp files, but there is an add-on available to enable it. Download the latest release from the project's GitHub page: https://github.com/RedHaloStudio/Sketchup_Importer/releases. You will want to download the .zip file.
In Blender, go to Edit → Preferences → Add-ons, click the little down arrow at the top right of the window, and choose “Install from Disk.” Navigate to the folder you downloaded the importer to and double-click the .zip file to install it. Once it is installed you will see it in the list of add-ons. Make sure the little checkbox is checked to enable it.
Note that I've only used this to import models created with SketchUp 2017 Make, though it should work with newer versions of SketchUp as well.
A quick side note for working in Blender - SAVE OFTEN.
I'll remind you about that later, but it's a good idea to save your work in Blender frequently so you can go revert back to the saved model if you mess up a step. If you want to be really careful, save incremented files (model_1.blend, model_2.blend, etc.) so you can go back to a specific point in time if you wish. CTRL-Z to undo is fine, but sometimes you don't realize you've made a mistake until a bit down the line so reverting to an earlier save is a safe thing to do.
Setting Up Your Blender Workspace
We want to have three separate “panes” to work in – one for the 3D Viewport, one for the UV Editor, and one for the Shader Editor. Mouse over the very bottom left corner of the 3D “graph” window until the icon turns into a small plus sign – then you can click and drag open another “pane.” Panes will, by default, duplicate the pane you dragged from, so the first time you'll wind up with two 3D Viewport panes. You can assign each pane to a different view by mousing over the pane and then clicking Shift-F10 for the UV Editor, Shift-F3 for the Shader Editor, and Shift-F5 for the 3d Viewport. There is also a small menu at the top left corner of each pane you can select from. The layout you choose is entirely up to you. This video provides a quick tutorial on how to split and combine the panes:
First, you'll want to delete the little gray box that Blender creates by default – just click on it in the 3D Viewport - it will be highlighted with an orange border when it is selected - and click the Delete button and it will go away.
You can now import the SketchUp model by going to File → Import → SketchUp and navigating to the model's folder. You may want to add a bookmark to the model's folder to make getting there quicker. When you're done you'll have a window that should look something like this:
In this view, the UV Editor is to the left, the 3D Viewport is to the
right of that, and the Shader Editor is below the 3D Viewport, but you can arrange them as you wish. You will also
see a couple of panels to the right side of the screen. Blender classes both
of these as “Data” views. The top one is set to the “Outliner” panel, which
shows a hierarchical view of the components, materials, and other assets in
your model. The bottom one is the “Properties” panel, which we'll be using a
lot. You can theoretically switch these views, but you really don't need to
for what we're doing.
Once the SketchUp model is imported, the first thing we want to do get rid of
the Camera and Light that get imported. You'll see them at the top of the
Outliner panel under “Scene Collection → Collection”:
Just click on each of those in the panel and Delete them. They are not
necessary.
At this point, it's probably a good idea to Save the model as a Blender file, which you can do from the File menu. I recommend saving often so you can always revert back to a previous state in case you do something you don't want to do or get lost.
Adding Sunlight
For a daytime bake, the first thing we want to do is add a sun to the model.In the 3D Viewport, make sure you are in “Object” mode from the menu at the top left of the pane and press the Z key and choose “Rendered” from the popup. That will give you a quick real-time view of what the lit model looks like.
Without a sun (or any light source) it's awfully dark, so let's shine some light on it.
In the Properties panel, click the “World” tab – it's the small red globe icon. Click the yellow dot next to “Color” and choose “Sky Texture” from the menu.
The World tab will now show some settings you can choose. I find the “Multiple Scattering” setting works best (older versions of Blender may call it “Nishita”). As you can see, the default settings are pretty severe:
I would dial the Sun Intensity down to about 0.300 and
Strength down to 0.500. Play around with the various strength and positioning settings until you like
what you see:
To make things easier on your computer once you're happy
with the lighting, you can go back to “Material Preview” from that “Z” menu in
the 3D Viewport. That will show you the textures without any lighting effects
so it's easier on the system since it's not doing any real-time rendering.
UV Unwrapping
In order to properly bake textures, the first thing we need to do is what's known as UV Unwrapping. Basically, what that does is take all of the selected faces and map them onto a flat image. When that UV Map is applied to the same faces, the image is "wrapped" around the faces. This is utlimately how OOTP's included 3D Models work, but the SketchUp model's UVs will be an overlaping mess (we'll see that below) so we need to properly properly unwrap the mesh in order to bake.From the list of “SKP Mesh Objects” in the Outliner, choose the component you want to bake. For this demonstration I will start with the “C-field” component. Click that in the Outliner and you'll see the field component highlighted in orange in the 3D Viewport:
You'll also see that the UV Editor has changed and it's a mess with textures overlapping each other, so we have to properly unwrap the component.
In the Properties panel, click the “Data” tab (the inverted
green triangle icon) and expand the “UV Maps” section. You'll see a UVMap
there, which is the one you are looking at. You can rename it if you wish, but
it's not necessary. What you want to do here is click the little Plus sign,
which adds a new UV Map. Again, you can rename it if you wish, but it's not
strictly necessary. Renaming the maps can help you keep track what you're
looking at. To rename the map, just double-click on the name in the list and
start typing. For this, I'm going to rename the field maps “field_original” and
“field_new.” The big thing is that you want to leave the “camera” icon active on
the original map and highlight the new map like so:
This will prevent Blender from messing around with any
texture scaling or orientation you have done in SketchUp. This is important!
Now back in the 3D Viewport, press Tab to go into Edit mode, or just choose it
from the menu at the top of the panel. Press “A” to select all of the faces in
the selected component. The selected faces will turn orange in both the 3D
Viewport and UV Editor.
From the Face menu in the 3D Viewport, choose “Triangles to Quads”, which will help limit the number of faces we're dealing with.
You may also wish to go to the "Edge" menu and choose "Mark Seams." That will convert every selected edge into a seam, which is what Blender use to unwrap. This works best if your component consists of a lot of large, simple shapes. Things like a component consisting of rectangular ads. If you want to get really precise you can manually select the edges you want to mark as seams by pressing the "2" key in Edit mode. That will shift into "Edge" select mode, and then...you can select the specific edges that you wish to mark as seams.
Over in the UV Editor, click the Image menu and choose
“New.” Give the new image a name. Because this is the daytime render of the
field, I'm calling it “field_day” since OOTP will use that to determine whether
to show the day or night texture down the line. The default image size is
1024x1024, but you can set it to whatever you want. The bigger the image, the
better detail you'll get at the cost of being more for OOTP to handle
rendering. Since the field is a fairly key element, I'm going to make it 2048x2048.
After naming and setting the size, click “New Image”. The UV editor
will show that new image – which is currently an empty square, behind the
various orange UVs.
Back in the 3D Viewport, press the U key (or click the UV menu) and choose
“Smart UV Project” from the menu:
Set the Island Margin to at least 0.010 and click Unwrap.
Hey, presto, the UV Map has changed!
If you're satisfied with the unwrapping, cool! If not you can mark or clear seams from the Edge menu and just re-do the Smart UV project.
The next step is telling
Blender what to bake where.
Day Texture Baking
In the 3D Viewport, press Tab go back to Object mode.In the Properties panel, choose the “Material” tab – it's the small circle with a red checkerboard in it. Scroll back up to the top to see all the materials in the component. If you see “DefaultMaterial” in there, it means you have some untextured surfaces somewhere. They are probably surfaces that aren't visible anyways otherwise you'd probably have noticed in SketchUp. Generally speaking, you can just delete that material without any noticeable change. Just highlight the material in the list and click the little “minus” sign to remove it. I'm going to leave it in for the time being to show how to work around it being there if you're not comfortable deleting it.
Now we're going to get into the Shader Editor. A quick note about the Shader Editor – navigating it is weird. There are things that it makes kind of hard to see because it's zoomed out so much. You can zoom in and out using the scroll wheel on your mouse and “move” the viewport around by clicking the scroll wheel and moving the mouse around. Making the pane bigger doesn't seem to scale it up, either. Anyhow…
Click the first material in the list of materials over in the Properties pane:
You'll notice that the Shader Editor is now looking
specifically at that material:
First we have to give it a “Source” UV map. Press Shift-A
and go to Input → UV Map
Click the little icon in the left and choose the “original” UV Map. This is not
the one you added, but the one we left the camera icon active on before.
Click the little purple dot next to “UV” in there and link it to the purple
“Vector” dot in the materials image box:
Now we're going to add a second UV Map. Same process to add it as before, but
we're going to assign the new UV Map we created earlier. Don't link it
to anything yet.
Then, again, Shift-A → Texture → Image Texture. This will be the
bake's target image.
From the little menu icon thing, click it and it will bring up a list of every
image the model knows about. You can scroll until you find the target you
want, or just start typing “field_day” to find it.
Then link the UV from the second UV Map we added to
the Vector of the bake target.
The next thing to do is simply click the bake target so that
it has a white border. This is critical since if you don't highlight
it, Blender won't know where you want to bake things to. When it's done, the
Shader Editor will look like this:
Now you repeat the process for every other material in the component. On the
bright side, you can speed this up by shift-clicking each of the 3 things we
added (they'll be highlighted in orange or white, with white being the last one
you clicked on) and copy them by pressing CTRL-C. You'll get a little
notification that you've copied 3 nodes down at the bottom of the window:
Back over in the Materials list, click the next material. Notice that the
Shader Editor looks like it did when we originally clicked the first material,
except the image box references the new material and its' source image.
Mouse somewhere into the Shader Editor and paste the nodes by pressing CTRL-V.
Where they get placed seems to be somewhat based on where the mouse is but it
also seems kind of random. While they're still selected you can click and drag
them around so they're not in the way. You wlll have to re-link the UV of the
original UV Map to the Vector node of the image, but everything else can stay
as is. Just make sure the bake target is still highlighted in white.
If you left the DefaultMaterial around, you'll notice there's no image. That's
because there isn't any! Blender will complain about that. To keep Blender
quiet, link the original UV Maps UV node to the “Normal” node in the
“Principled BSDF” box.
We are now almost ready to bake!
Back in the properties panel, click on the “Render” tab (the icon looks like a
digital camera). Make sure the Render Engine is set to Cycles. If you have a
decent graphics card, set the Device to GPU Compute to help speed things
along. Under the “Render” section, lower the Max Samples. The higher that is,
the higher quality the render will be, but the longer it will take. Since at
this point we just want to make sure the bake is working at all, set it to
something low. Something like 1 or 4.
Scroll down and you'll see a Bake section. Expand that and set the Bake Type
to Diffuse and leave all three of the Contributions under “Influence” checked.
Then…click “Bake”!
Down at the bottom of the screen you'll get a small progress bar, followed by a
confirmation that the Baking map has been saved to an internal image.
And now over in the UV Editor, you will see the baked texture behind the UV
grid!
Once you're happy with the rough bake, go back and increase the Max Samples to
something lie 128 or 256. The higher the number, the higher quality the bake,
but the bake will also take longer.
Once you've finished baking and if you like what you see, save the image.
Blender won't save it automatically for you! In the UV Editor, just choose "Image → Save."
By default, it will save the
image as a PNG file with the name you gave it in the same folder your model is
saved in:
Repeat this process for every component you wish to bake.
There will probably be elements you don't want to bake shadows into, such as backlight signs, LED ribbons, and the crowd (since we'll be replacing that texture with the 3D crowd anyways). See the next section on that.
I would suggest you save your work after each successful bake to make it easier to revert back.
Baking "Backlit" Textures
As I mentioned earlier, there are some textures where baking is perfectly fine but you won't want them to react to ambient lighting. The UV unwrapping and baking process is the same with two minor changes.
Set the Bake to Diffuse, but uncheck the "Direct" and "Indirect" checkboxes. That will cause Blender to bake the texture without any lighting effects.
Optionally, set the Max Samples to something really low. 1 is fine. Since we're not dealing with any lighting, there's no benefit to slowing the bake down.
Other than that, the process is the same.
OOTP Specific Textures
OOTP, as you probably know, handles 3D crowds and live scoreboards by actively replacing the textures. To avoid odd behavior, you'll want to exclude these from the baking process. Baking them will just cause problems for OOTP as the wrapping will just confuse the game engine, so it's better to just skip these entirely.
For the live scoreboard you may need to place a dummy texture in the model's folder and point the MTL file to that. The crowd textures you just replace in the MTL the same way we've been doing for years now.
Save a Copy for Night Baking
Up until this point, everything we've done has been with a "daytime" bake of the model in mind. But it's entirely likely that your ballpark will also need a nighttime bake. Since the steps in the next section will replace the model's textures with the baked textures, we'll need to have a separate "clone" of the model for the nighttime bake, and this is the best time to do that. That way, you'll have a copy of the model with all of the UV unwrapping done, but nothing permanently baked into the model.
From the File menu, choose "Save Copy" and call it something like "ballpark_night.blend" or whatever helps you keep it straight.
Using the Baked Images
In the 3D Viewport, make sure you're in Object mode and press “Z” and set the view to Material Preview. You'll notice that the field looks…just like it did before you baked. Nothing has changed. So how do we use these images that we've baked?Back in the Materials tab over on the Properties panel, highlight each material in the component and click the minus button to delete it. This is a one-by-one process. When you're done, there will be no materials in the list and the component will just be…gray.
This is actually what we want to see. Click on the plus button next to the Materials list to add a new material slot, and then click the “New” button below the list.
Give the new material a distinctive name – in this case, I'm going to just call it “field.”
We now have to make the “new” UV Map active – in the “UV
Maps” Section of the Data tab, click the camera icon next to the “new” UV Map.
You will notice that a new pair of boxes appeared inside the Shader Editor when
you created the new material.
What we're going to do here is similar to what we had to do to set up baking. Add a new UV Map (Shift-A → Input –> UV Map) and a new Image texture (Shift-A → Texture → Image Texture).
Set the new UV Map node to use the “new” UV Map (“field_new”),
and load the field image you saved a bit ago into the Image node by clicking
the “Open” button and choosing the appropriate image.
Link the UV node from the UV Map to the Vector node of the Image, and link the yellow
“Color” node of the Image to the “Base Color” node of the Principled BSDF. The
Shader Editor should look like this:
And up in the 3D Viewport, look at that!
Congratulations, you have successfully baked a component and applied the baked
texture to the model! Now all you have to do is repeat that process for every component in your model. :D
Exporting the OBJ file
To see how it looks in OOTP, we'll need to export this to a format that OOTP can understand - the good old OBJ format, same as we've been exporting from SketchUp for years.Go to File → Export → Wavefront (.obj). It will default to the same folder the Blender file is in. For the purposes of this tutorial I am saving it in a subfolder called “baked” but it really doesn't matter. One very important thing to note is that you have to set the Path Mode to “Copy” – scroll down in the right side of the save dialog and set it – this is important. After you've set that, click the "Export Wavefront OBJ" button.
If you look in the model's folder, you'll notice we have the .obj, .mtl and baked texture file(s) all in the same folder:
And if you load that model into OOTP, you'll see your lovely shadows on the field!
Setting Up Night Lighting
Now is when we open up that _night model we saved before applying all of the daytime baked textures. File → Open → (modelname)_night.blend
The first thing we have to do is dial down the sunlight so that it's just providing a bare minimum of ambient light - that will prevent any textures that aren't getting stadium lighting from rendering completely black. In the World tab, set the Sun Intensity down really low - I just set it all the way to 0. Set the Sun Elevation to 90° and the Strength down to something like 0.02 or 0.03.
If your 3D Viewport is sent to "Rendered" you'll notice that the light has gone almost entirely away.
The next step is to get the light towers to actually emit light.
In Object mode, select the light source you want to work with and then go into Edit mode. Make sure you're in "Face Select" mode (press the "3" key) and select the face that have the "light" texture:
There are two different ways to set up lighting for our purposes - one is more generic, one is more granular.
For generic lighting, go back into the Materials tab and select the material that represents the acutal lights. Expand the "Surface" section and then expand the "Emission" section from there. Make sure the Emission color is set to white (which it should be by default) and then crank up the strength until you're happy with how it looks. You'll probably need to turn it up a lot. You can also access those settings in the Shader editor, but it's easier to see in the Properties panel. This will apply the same lighting emission settings to every instance of that material.
If you want more granular control over the lighting, you can create a new material slot inside each component to act as an emitter.
In Edit mode, make sure the faces containing the light's texture are selected. Then, in the Materials tab, add a new material slot by clicking the plus sign next to the list of materials. Give it a distinctive name such as "floodlights_1". Then click "Assign" to assign that material to the selected face(s). When you do that, the face will just become a blank white space which is good enough for our purposes.
Just like above, set the Emission strength and color to your satisfaction. But this time it will only affect that selected component.
When you're done, you should have a nicely lit ballpark.
One thing to note is that an "emitter" emits light in a 360° sphere, so it's sending light in all directions. You can contain this light by adding a surface into your model in SketchUp to act as the "back" of the lights. That should block the light from going in any directions you don't want it to go. But, honestly, for our purposes that's really overthinking things.
Night Texture Baking
Since you've already UV Unwrapped your components, baking the night texture follows the same procedure as the day bake. Everything is already set up, in fact! Internally, Blender will use the same bake target images we created earlier.
There is one thing you'll have to pay attention to, and that's shared materials. SketchUp can reuse the same texture file in multiple components. So if you use a concrete texture for the concourse and also use it in the scoreboard (like I do in the tutorial model), every time you set up the shader, it will ripple out and affect every other instance of that material. Blender makes it pretty obvious when there are issues by highlighting them in red:
All you need to do is adjust the highlighted items to be consistent with the rest of the materials within the component. Pay attention to both UV Maps as well as the bake target image, and also make sure that the target image is selected by clicking on it to highlight it in white.
The main difference - once you've finished baking and if you like what you see, save the image with the _night name. As before, Blender does not automatically save the image. So in the UV Editor, just choose "Image → Save As."
When you save the image, just be sure to change _day to _night! This, of course, is consistent with what OOTP expects for determining day and night textures.
When you're done, you'll have day and night textures ready to go!
As a side note, you can skip re-baking any of the "lit_" components. Since OOTP only loads the night texture if it finds one, just having the day texture works fine.
Troubleshooting / FAQ
As I go through the components, sometimes the materials already seem to have UV Maps and bake images assigned to them and have some things highlighted in red, why?
Generally that's because it's a material that is used in more than one component, and which you've already come across. Each material can only have one Shader setting, and it follows the material around every time it's encountered. The red highlights are because those UV maps & images are not "found" within the context of the component. All you have to do is just adjust the red highlighted items to match the other materials found in the component and you can bake normally.
When I bake, some of the textures are baking as completely black, how do I fix that?
What's happening there is that the faces baking black are still somehow facing the wrong way. Luckily, it's fixable in Blender.
In the 3D Viewport, open the "Overlays" menu - it's the one that looks like two overlapping circles - and check the "Face Orentation" checkbox. Any faces that are backwards will become highlighted in red. In older versions of Blender, front-facing faces will become tinted in blue, although Blender 5 changed that so that the blue tint is completely transparent.
In Edit mode, press the "3" key to enter "Face Select" mode. You can also click the small icon that looks like to overlapping rectangles.
Select the faces that are facing the wrong way and choose Mesh → Normals → Recalculate Outside, and the selected faces should flip the right way. If not, there is an explicit "Flip" option in that menu if you need to do anything more detailed.
Then try baking again.
During a bake, I got a message saying "No active and selected image texture node found in material "material name" for object "component name". What does that mean?
Simply put, that means that the bake target image is not specified for that material. Go back through the materials list for your component and ensure that the bake target image is selected and highlighted in white.
After baking a texture, I clearly miscalculated how large the bake target needs to be. How can I fix that?
In the UV Editor, just click on Image → Resize and enter your new desired size. The image will scale up or down accordingly. Then simply re-run the bake and it will bake to the new size.
Resources & Files
Blender Tutorial Model (Night)