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For part two of my tutorial on Source model posing parameters, I'm going to go over how to make your tyres on your buggy model we started in part one have spinning and rotating tyres. If you missed part one, you can find it here:
Open your scene from the last tutorial (you did save it right?), and it should look like this:
We need to add several bones to our scene:
Tyre, Front, Left, Steering
Tyre, Front, Left, Rotation
Tyre, Front, Right, Steering
Tyre, Front, Right, Rotation
Tyre, Rear, Left, Rotation
Tyre, Rear, Right, Rotation
Here's a crap diagram of what we need for a tyre to correctly rotate:
As you can see, the front wheels need two bones each because one is for the 360 rotations, and one is for the -20 to 20 degree rotations that the steering provides.
Zoom in on your front tyre, whichever one you wish to work with first:
First, we need to make our new bones, so as I told you have before in part one, make a new bone with Create > Systems > Bones IK Chain and left click, drag, left click, right click where you want to make your front tyre bones. The left click makes the first bone, dragging sizes it, left click creates the rotation bone, and right click makes the rotation bone a cap and ends the chain.
You should now see something like this:
As we did before in part one, we need to make our rotations exact, so at the bottom of the screen you'll see a few bones that I've circled:
In part one I told you how pressing F12 would open a little window that would allow you to input exact values for movement/rotation/scaling; this set of boxes is basically a shortcut to the F12 menu. They do the same thing but are always on the screen.
Depending on which side you did first, the Z-axis on rotation will either be close to 180 or close to 0. Make it exactly 180 or 0 depending on which side you're on, and make sure that the child bone you also created is the same orientation.
We need to duplicate our steering bones for this part, so now with both bones selected, press CTRL+V to clone them and it should pop up a menu. Alternatively, sometimes the menu won't directly open, and you can clone them by going to Edit > Clone and opening the menu manually:
When the menu opens, you should see this:
Make sure that COPY is selected, not instance or reference, otherwise it won't work correctly.
Now, you'll have a copy of the bones selected and they'll be in the same location; activate the movement tool, and translate them over along the single axis to the other front tyre.
After you moved them, you should see this:
We need to rotate the base bone in this set to face the opposite direction, so now with only the base bone selected, rotate it to either 0 or 180 depending on which side you did first, and it should now look like this:
We're now ready to create our rear tyre bones.
Zoom in on one of the back tyres:
Make sure the bone is centered and rotated to either 0 or 180, and then clone, move, and rotate it to the other back tyre:
Now we're ready to name our bones. Select the bones one by one and name them the following:
Front Left Root: tyre_fr_lf_st
Front Left Child: tyre_fr_lf_rot
Front Right Root: tyre_fr_rt_st
Front Right Child: tyre_fr_rt_rot
Rear Left: tyre_rr_lf_rot
Rear Right: tyre_rr_rt_rot
The way to look at these names is like this:
tyre_ - the tyre bones
fr_ - the front side
rr_ - the rear side
lf_ - the left side
rt_ the right side
st - the steering bones
rot - the rotation bones
When you get into a groove of modeling or model working at all, it's nice to have some pre-confirmed naming conventions that are standardiazed across your works. This not only saves you time because you'll know what is what each time, but it will also save time to anyone who encoutners your workflow by letting them know at first glance what is what.
After you've named your bones, we need to move them up to the center of the tyres, because right now they're at the grid base line, and that's not what we want.
Select the front two tyre root bones, and move them upwards until they're at the center of the front tyres:
Do the same for the back tyres:
Now we need to parent them to our "base" bone from tutorial part one.
Press H to open the selection panel and make sure your bones look like this:
Make sure you've only got your base wheel bones selected on the front, so that these bones are selected:
Now as we did in part one, using the linker tool (the chain links at the top left) link these to the base bone by selecting the wheel bones I showed you, pressing the link tool, and then press H to re-open the selection menu, and link them to the base bone:
De-select the link tool by selecting the selection button:
Now your child bones should appear like this in the selection menu:
We're now ready to start weighting our mesh again!
We need to add our new wheel bones to our skin weight modifier on our main mesh, so select the main mesh as go to the modifiers tab as I showed you in part one, and add the new bones:
Now we need to hide most of our mesh. First, we're going to weight the back tyres, so hide everything but the back tyres by going to the "Editable Mesh" modifer and selecting the "Element" selector:
Now with one of the rear bones selected, weight the rear tyre as I showed you in part one, by clicking on the weight paint tool icon that looks like a wrench:
And click the one key:
Do the same for both back tyres, and now we need to hide them.
On the front tyres, we need to do something different, so we need to only show these two parts of the front tyres:
One is the front tyre element itself, and the other is a smaller cylinder on the outer part of the front tyres. Weight both parts on their respective sides to the "rot" bones.
After that, we need to unhide the rest of the mesh, and then hide everything EXCEPT the following shown two parts:
These two parts that are left on each side need to be weighted to their respective "st" (steering) bones. Do that now.
We're now ready to start exporting our frames!
As I mentioned in the video for this part (linked at the bottom) the turn poses in our last export won't retroactively include our front wheel rotations, so we need to export them again.
Do the same thing we did with our steering wheel, and rotate it on the local axis 60 degrees to the left:
This time, though, before we export we need to rotate our front steering bones 20 degrees each to match our rotations.
Select the steering bone for one of the front tyres in the selection menu (the ones with _st in the name) and rotate it 20 degrees like this:
Do this for both tyres, and then we're ready to export them as I showed you in part one:
Make sure to overwrite the original. Do the opposite for the steer right rotations:
Export the "turn_right" sequence .SMD, and then reset the rotations and export your "neutral" sequence .SMD file.
Next, we need to export our tyre rotation frames. For each 360 we want our tyres to do, we need to make at least 4 frames, one for each multiple of 90 degrees.
First, export the scene as-is and name the exported file "tyre_0". You should already have the export steps down so I won't show them to you again. Remember to only export one frame!
Rotate the "rot" bones 90 degrees forward INDIVIDUALLY. If you do them all together, the sides are going to go the opposite way because they have different base rotations.
After you've rotated them 90 degrees forward, export this file as "tyre_90".
Do it again it rotate each tyre's "rot" bone 90 degrees and export the scene as "tyre_180".
For the next step, repeat as before and export it as "tyre_270", and then either undo the tyres back to 0, or rotate them individually.
Now we need to export our new reference mesh .SMD because our old one doesn't have the new bones included in it and it will give errors.
Remember to have "Use Explicit Normals" selected in the check boxes!
Now we're ready to move on to the .QC file editing!
As before, I'm providing you with a pre-made .QC file that you can snag on PasteBin: