Fusion
Problems with thicken are almost always from areas of high curvature. High curvature results in self-intersecting surfaces, which cause the failure. Applying a curvature map to this surface shows areas of very high curvature (the purple areas):
So, one approach is to try to fix those. There is another approach, though, since this is a T-Spline model. There is a Thicken operation in the Sculpt/Form environment, that is generally much more forgiving. So, I tried that. I was able to get close at 1mm. See the screencast. There is still some self-intersection in the offset. Once I finished the screencast, I went back and made some modifications (all around the eye sockets) that eventually led to success at 1mm. That model is attached, if you are interested.
Now, there are probably things in your T-Spline model that are undesirable (triangle faces, "star points", etc) that may also be contributing to the problems, but I'm not an expert on those.
Jeff Strater
Engineering Director
I am not probably the best person to recommend T-Spline usage patterns. @TrippyLighting is much better at that (as are many others). I've just memorized the "don't use triangles", and "star points are OK, if used carefully" talking points. I can usually get near the shape I want using them, but am probably not a role model.
Creases are an interesting topic. They have their use, but can be abused. I tend to think Solid or Surface when I see sharp corners, but creases were added for a reason in T-Splines, so they should be OK, if you don't over-use them. I don't think this model does that. I tend to just add extra faces (insert edge, insert vertex, subdivide) when I want more curvature in an area, but that approach will always leave some curvature.
Also, you should probably periodically look a the model in Box mode. Self-intersections are usually more apparent in Box mode. Try to get a nice-looking Box mode version, and the resulting smooth model will be nice, also.
If you are designing with the idea of thickening in the end, I might be tempted to throw a curvature map on it from the start, and watch out for those purple areas.
The other thing I forgot to mention about T-Spline Thicken: It is not associative. Once you've thickened an area, your opportunity to adjust the form is limited. So, if you can get away with Thicken in the Solid area, I'd stick to that. T-Spline Thicken is really a bit of a cheat that can get you out of a tight spot sometimes. A good too to know, just know its limitations...
Jeff Strater
Engineering Director
I echo much of what @jeff_strater says.
1. For a beginner NO triangles and no N-Gons (polygons with more than 4 vertices).
2. Model at least 70% in Box View mode. Check the shape in smooth view mode. If you make small adjustments in smooth view mode check back that everything is OK in Box view mode.
3. Polygons should not be overly stretched. If you need to stretch a polygon very far to get the shape you want, More geometry is needed (edges, polygons)
Check out the links I provided her in this thread!
Also, creases can work well if applied at the end of the modeling process. If you continue tom model with crease applied you'll find that often the model exhibits hard to explain artifacts and that can already be seen in your model.
Your model isn't actually bad. It just needs a little TLC 😉
Modeling human anatomy, even "just" a mask is hard!
@junkPH3JH wrote:
I'll do a bit more learning on my own and continue to work on this..
Follow the link in my post to the other thread and when there, follow the links I provided there.
Just practicing alone isn't going to cut it. You'll also need to familiarize yourself with a little theory.
@junkPH3JH wrote:
Thanks Peter! That is how I spent my evening last night.... falling down a sub-d rabbit hole 😉
LOL. I know how that goes ...
I took this to Blender, because I can work more fluidly. However, that topology can also be created in Fusion 360.
I've you've watched some of Arrimus 3D Blender videos, you'll notice the he uses the Knife tool often to cut in additional edge loops.
Fusion 360 has a very similar tool but it has the most unintuitive name. It's the "Insert point" tool.
So around the eye and the cheek bone area you'll see a number of loops added to tighten up edges better.
However, I also work with crease in Blender. Creases in Blender are weighted, which means they don't have to create infinitely sharp edges. That can often help in reducing support loops. The purple edges are creased.
Here's how that looks in Fusion 360 with creased edges.
Model is attached.
Ne more thing: It is generally advisable to avoid face loops like this:
`Here is a model with all creases replaced with proper support loops:
Thickening will be it's own challenge. This should be done with the T-Spline thickening command. That will create a lot of self intersecting geometry in areas of high curvature , which will need to be fixed manually.
