Seek advice on truncating a spheroid in Blender.
lukon100
Posts: 809
I want to model the Kaldorian space ship from Space 1999.
https://catacombs.space1999.net/main/models/w2mkaldor.html
And I see that it would involve truncating a spheroid in 3 places, 120 degrees apart.
And I don't want to use the boolean modifier, as that always leads to crappy geometry near the cuts.
Or does it? Is there a way to get clean geometry with boolean?
Well, anyway, I seek advice on how to do this right in Blender. Maybe someone can direct me to a nice video tutorial on it.
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For specific advice on modeling techniques I guess you'll be better answered at blender artists, since here on daz most of us import from daz studio. I myself am not good at modeling hard surfaces. Of course you could also go with sculpting and retopology you can do anything that way, but it's not fast.
You can also use subdivision, below I cutted a simple hole in a sphere for example.
If you have good geometry to start with, booleans have a better chance of generating decent geometry. It's often better to fix the original geometry. Here, you will likely get an ngon where you truncate; that need not be a problem if you're not exporting to software that has an allergy to ngons, like Daz Studio does. Or delete the ngon face and fill it with quads/tris.
You could get a similar effect using a lattice modifier. You might have to bevel round the edges if you want sharp edges round the flat areas.
Josh Gambrell on Youtube has some videos dealing with hard surface modelling using booleans, the problems that can cause and how to fix them.
No need for booleans. Select the verts you want to have 'flat' and scale them to zero in one direction in edit mode.
Can Blender change the workplane so that the axes for scaling lined up with the area to be flattened? Hexagon can, as can modo.
Another option might be to delete the mesh you need flattened, then path it in with new geometry with the desired flow and flatness. Or delete, model a flat area in the void with a bit of space around, and bridge across to get a smoother join.
Doesn't even need to. Just create a 120 degree segment that aligns with the axis you flatten it on and make two copies, each rotated by 120 degrees .
True, though it looks as if the Normal axis system may function as a near equivalent to a custom work plane.
I'd copy the sphere, use a boolean intersection modifier on a cylinder with 3 sections, and then use a shrinkwrap modifier on the copy. You could probably get away with hitting F3 and searching for the Convert-To-Circle add on to fix the hole, scaling it to taste, and moving it around with the shrinkwrap modifier still active.
Also, instead of doing the work 3 times, start with a sphere with a number of sections evenly divisible by three, delete the other two later, and then use an array modifier with object offset, 120 degrees, a count of three, and merge vertices.
@lukon100 Works fine without forcing it to a circle, IMO. The topo is fine. If you decide to play around with it and change the z scale of Sphere, you'll have to copy that scale to Empty, or else each element of the array will grow; not what you want. I was too lazy to set up a constraint, but that is not hard... and as it is, it's 100% procedural, so you can art direct it non-destructively.
Edit: Aaaaand... notice that I forgot to select Merge on the Array Modifier.
If I'm understanding correctly, you can click the plus sign by the Transform Orientations, and select an object whose transforms you want to use.
Many ways lead to Rome. Thb, you could use a cylinder, loop cut, scale the first edge down a bit, mark edges, use a subsurf as well :)
I'm using SubD a lot, you get very nice organic looking shapes. However every method has its pros and cons. If I would go with bools, I would tinker about where to add some support loopcuts.
A big help is mesh machine with the offset feature or boolean cleanup. Normally I do this by hand, if there are minor problems, and use matcaps a lot to detect any shading glitches. Best to wait for black friday :)
EDIT: Forget about it - I've overseen the 120 degrees, my bad! However I'll let this text above, maybe helpful for other things.
Sorry I abandonned this post for so long. I had no idea so many folks were replying to it.
Well, I must say I don't understand half of what is being discussed here.
But while I was away, I went ahead and experimented with some boolean cut methods. And I have settled on one for now. It is not perfect. See my attached Daz Studio iRay picture where some of the jerky faceting can be seen in the right lighting angle, inside where I have outlined in red. So, while not perfect, I find it good enough, as it is complementary to the geometry resolution in general.
You can also see that I made some triangular boolean cuts for the rocket blast ports.
My next conundrum here is the texturing. How do I place all those little markings on the model with good radial symmetry? The markings I have so far put on are done with differing material zones of the geometry. And this works ok for the triangles, but it won't do for the little dots. I'll likely have to resort to a full on UV image map. And that seems a bit scarry to me right now.
Seems to me that would only produce a nice sharp edge if I had super dense mesh, a mesh so dense it would send every scene using the ship model into CPU render instead of GPU render.
Ya ya! I definately put supporting edges in, using the Face/Inset tool and re-allignment of some subsequently wonky vertices.
Ya. I was considering using shrink wrap, but not for how you were suggesting. I was gonna use shrink wrap to help me blend two UV spheroids together.
One UV spheroid aims it's generative axis forward, on the Y axis in Blender. This makes it easy to make the elliptical flat for the ship's door. No boolean cut needed, so it looks perfect. Cut the other 120 degree sections off that UV spheriod off, like you said, and splice copies of the forward facing door section in those absent sections to complete the UV spheroid again and merge doubles. Sub-d as needed to get nice smoothness. And this becomes a good shrink wrap target block.
Now, because I want a nice radially symmetrical UV map, I need to make another version of the sphereoid with the genrative axis vertical, on the Z axis in Blender. So I go ahead and make that spheroid.
Now I want to splice the two spheroids together. So first I make a copy of the first spheroid to be the shrink wrap target block. Then I splice the two spheroids together by deleting from one of the spheroids what I want defined by the other spheroid, and vice versa. Then join the partial spheroids and connect them together with manually placed edges.
As I imagine my new spheroid will look a bit messy where I had inserted my joining edges, I was hoping that the shrink wrap process would smoothen out that mess, and bring the whole thing into proper contouring.