Backhoe Contribution – duerer – Wheels / Rear Axle

[Shawn Blanch]

It looks like a modeling cornucopia! 

[Ingmar Franz]

It sometimes looks to me like a new version of “Battleship Galactica” 😉😁.

[Ingmar Franz]

I finally managed to get an all-quad-retopo of my rear axle end housing but it still causes a really bad shading especially in the area where the green bolt holder is connected to the red main body:

File is here.

[Ingmar Franz]

I think that a “Topology Basecamp” here at CGCookie with training of how to clean up problematic topology (N-Gons, poles, triangles etc.)  would be a good idea. I’m thinking at something what William Vaughan does in the two volumes of his “Topology Workbook”. But the examples described there are mostly with flat planes and not with closed surfaces like my rear axle end housing above.

[Ingmar Franz]

By the way: Can anybody explain this in my eyes arbitrary color bleeding in the areas of the beveled edges?

PS: I just found out that a complementary color bleeding effect with swapped colors can be achieved by calculating the normals inside.

[spikeyxxx]

@ duerer I had a quick look at your file (don’t want to look at it too much, because I am at the moment also struggling with the housing and I do not want to get ‘prejudiced’/torn into doing it in a certain way…) and the problems (both the shading and the random color bleeding) are caused by your use of the Bevel Modifier…

If you apply it and look at the geometry it creates (set the distance a bit higher so you can actually see what’s happening), you”ll see the mess: concave n-gons and poles to give you nightmares…No mesh like that could survive a Subsurf!

I’d never use Bevel Weight with a delicate mesh like this and make sure I’d have full control over the topology, but of course you are free to use any method you like, but at least use more than 1 segment on the bevel (best 2, just like when you use edge loops to control the sharpness of an edge, you’ll put one on each side…)

It’s a difficult part. I will post my file when I’ve finished the housing in my thread (with just the housing), so you can see how I did it. Maybe that will be helpful in some way.

[Ingmar Franz]

Thanks, @spikeyxxx for your tips. The “Bevel Modifier” is certainly not easy to use since you can easily mess up things with the wrong settings and on such a complicated part like this, it’s obviously better to use holding edge loops. Changing the “Inner Miter” type from “Sharp” to “Arc” makes things even worse. But it was worth a try.  The axle end housing is by far the most difficult part that I’ve modeled on the rear axle.
Another difficulty for me is to contain additional geometry as local as possible. But when it fits in one part, it often does not / no longer fit in another part. Furthermore, keeping geometry as local as possible can generate a relatively dense geometry which will be visible as sharp edges in smooth shading like scars. It’s a really sensible balance that you have to keep and just a little step too far to the left or to the right can produce a really ugly result. Nonetheless, this part is an excellent opportunity for training your skills in terms of creating a clean topology and my top candidate for a future “CGCookie Topology Basecamp”.

[Ingmar Franz]

@blanchsb your video is really helpfull and looks as if you were already part of the CGCookie crew for years. I’m wondering when they  will offer you a permanent job in their team 😀.

[Shawn Blanch]

@duerer  the Mesh Modeling Bootcamp by @jlampel really helped me wrap my head around topology better. I went from bad topology to not as bad to decent. I still make mistakes a lot but doing that learning flow really helped. The other tidbit from @theluthier that I am terrible at is: get the main outside edges all sorted then sort the detailed extrusions and give them good holding edges that take all of the push and pull from a Sub-D mod and then work your way connecting the two and figuring out the n-gons and poles on fairly flat areas. Hopefully that makes sense. Watching his live stream working out the rear digger arm and details was very helpful. I want to go back and watch that a few more times because I still forget to do that.

Now granted you’re and Spikey’s job is an extreme situation where very little geometry isn’t going to be a challenge. I almost wonder if modeling things on a flat plane and then wrapping them into circles and joining them would maybe be a clever way of working with cylindrical objects??? Or maybe I am just rambling? @spikeyxxx has really good ideas when it comes to this stuff. I want to see more WIP pictures Spikey!

[Ingmar Franz]

Thanks, @blanchsb, for your hints! The challenge with the axles is that there’are a lot of curved and straight surfaces intersecting and flowing into each other. Adding a new part on curved  surfaces so that it doesn’t distort your curvature especially in that relatively small space is very tricky and frustrating. As soon as it fits in one place it often causes problems in another place.

[Ingmar Franz]

Okay, here’s a new version of my rear axle end housing without “Bevel Modifier” and with holding edges instead: 

But the shading issues due to bad topology in the red main body and the green bolt holder remain: Either I get pinching because of too dense mesh parts or  too big parts on curved surfaces cause problems. I’m somehow turning in a circle where, when I solve an issue another one  arises. File is here.

[Shawn Blanch]

Hmmmm…… do you have the original booleans where it is more smooth? One idea would to implement the shrink wrap approach on the troublesome areas and move the base mesh. Kent covered this for @adrian2301  during the 2nd or 3rd live stream. I think that this will probably could help solve that. 

Or on a more manual but more controlled approach you could reference the booleans OR duplicate the red part and close it up and snap the green section to that smooth duplicate perhaps? Treat it like the Zerk fitting that Kent also made. He was using booleans for that workflow and then snapped the retopology to the simple boolean shapes (livestream 3: timestamp 2:57:00)

[Ingmar Franz]

@blanchsb, thanks for the tips! I’ve already removed all booleans and replaced them by manually modeled mesh so that I have the best control (at least theoretically if I were more skilled on that  😉 ).  The “Shrinkwrap” method is certainly worth a try allthough I fear that it’s a little bit more setup work on this complicated mesh 🤪.

[spikeyxxx]

@duerer I think @blanchsb ‘s suggestion of a Shrinkwrap is definitely worth the trouble here.

Your surface is a bit wobbly now:

and:

Those are the ones that immediately caught my eye, but there are probably more areas like this and trying to manually correct them will be a nightmare and the results will never be great…

[Shawn Blanch]

You can append an older submission to get those booleans back if they are the same size perhaps?

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