I haven't posted for a couple of weeks because I have been a bit busy getting the bogey animation to work. Big Bertha uses Walschaerts Valve Gear but somewhat differently from the normal. Or so I believe. 
I thought I had it sussed until I tried to export the animation and came a cropper. I forgot rule 1 in animation which is you cannot animate the mesh. You must animate the lattices. You would not believe how much rework that required.
My animation currently has four armatures, eight bones and I haven't counted the lattices but there are lots of them. I've even gotten into the habit of naming my bones rather than using .001 and .002. Some lessons must be learned the hard way.
And I've learned a whole lot more about Walschaert valve gear. I can even get the spelling right the first time.
Despite a few setbacks I think I am making progress. Perhaps the hardest part has been understanding how Mr Fowler implemented the valve rod, lifting arm and expansion link on Big Bertha. I believe the drawing I have shows this gear in neutral and all along I was thinking it must be in forward. I hope I am right and when this thing finally gets uploaded maybe someone will point out my mistakes.
Here is a pic of the gear in Blender. I have hidden the armature located at minus 100 metres as it totally obscures the view. But you can see the eccentric rod armature, the connecting link and combination link armature and the difficult valve rod armature. They are all offset well to the left because it gets rather crowded where the meshes are located. I'm still working on the positioning of the connecting link and combination link meshes, and the valve rod mesh.
When it is working to my satisfaction - probably a week away - I will post some more pictures and more information on lattice usage which is significant.
Paul
I thought I had it sussed until I tried to export the animation and came a cropper. I forgot rule 1 in animation which is you cannot animate the mesh. You must animate the lattices. You would not believe how much rework that required.
My animation currently has four armatures, eight bones and I haven't counted the lattices but there are lots of them. I've even gotten into the habit of naming my bones rather than using .001 and .002. Some lessons must be learned the hard way.
And I've learned a whole lot more about Walschaert valve gear. I can even get the spelling right the first time.
Despite a few setbacks I think I am making progress. Perhaps the hardest part has been understanding how Mr Fowler implemented the valve rod, lifting arm and expansion link on Big Bertha. I believe the drawing I have shows this gear in neutral and all along I was thinking it must be in forward. I hope I am right and when this thing finally gets uploaded maybe someone will point out my mistakes.
Here is a pic of the gear in Blender. I have hidden the armature located at minus 100 metres as it totally obscures the view. But you can see the eccentric rod armature, the connecting link and combination link armature and the difficult valve rod armature. They are all offset well to the left because it gets rather crowded where the meshes are located. I'm still working on the positioning of the connecting link and combination link meshes, and the valve rod mesh.
When it is working to my satisfaction - probably a week away - I will post some more pictures and more information on lattice usage which is significant.
Paul