The problem is that the detail that needs to go into this area simply doesn't exist in the original footage,
Since it was now clear that using the original footage to provide a decent
map for a vehicle wasn't going to work, I had to take a different approach.
This time I decided to do it properly...
I took front and side photos
of my car, and used them as reference for making a fairly simple HyperNURBs
model of the car. I then (after some tweaking in Gimp) used these images
as projection maps for the car.
The only complication with this is that I needed the material to blend
between the two photos, depending upon position on the model.
For this I created a mask channel with intensity dependent upon the surface
normal direction. The closer the surface normal is to pointing towards the
'front' or 'back', the brighter the mask, and the closer to the side the
darker. A colourised version of this can be seen here (the actual mask is
As you can see below, the car model is quite simple. The only details are
the wing mirrors, since they stick out enough that it's noticeable if they
aren't there. the rest of the car is just a simple HyperNURBs model (Subdivision
Surfaces). Note that the surface colour in this image is determined by the
mask channel based on the surface normal.
Projecting the front photo onto the model without the mask:
This looks fine from the front, but on the sides it has the same problems
as the van had, due to the absence of detail in the photo for the side surfaces.
Using the side map only gave the following:
This time the sides are fine, but the front and back aren't.
Finally, this is what the model looked like with both maps applied and using
the normal dependent mask to selectively fade between them depending upon
which part of the model is being considered.
And that's the final model as used in the shot. It doesn't stand up to close scrutiny,
but it's good enough for the shot that it was made for.
of a third photo taken from above would remove the remaining texture stretching
that you can see around the top and bottom of the windscreen, since in that
case none of the photos would be projected as the main texture at an angle
worse than 45 degrees. The next most obvious defect in the model (I think)
is that the seat headrests are projected onto the windscreen because the model is solid and has no internal detail.
If anybody is reading this stuff and finding it useful, then let me know, and I'll try to write more.