I’m having some trouble modelling my desired surface for a product for our design studio. I have highlighted the surface in the first screenshot n.1, this is the inner surface of the ‘bowl’. What I’m after is a smooth/soft surface, I don’t want it to have a steep dish but quite a gradual curve profile. I have tried, rail revolve, and sweep 2, these both gave me quite hard grooves near the fillets/corners (please see screenshot n.2 outlining grooves). Curve network, gave me pinch points where small parts of the surface were distorted, I didn’t think this would be the right method to be honest. Loft has surprisingly given me the closest result to what I want (please see screenshot n.3 and see no grooves). However, this does not give me any control over the profile curve. I split the model into sections to get a closer look at the cross sections of the dish and these varied massively, with one segment curving out slightly and then back in (please see screenshot n.4) I realise I might be expecting too much of the commands to do it all in one go - too much heavy lifting. If anyone could help me that would be GREATLY appreciated.
Hi Bex - you have some fairly abrupt corners in the top curve, I don’t know if you’ll be able to stop those from propogating into the surface for some distance - these corners are tangent and not curvature continuous so it makes it even a little trickier to fade them cleanly, if that is the goal.
I’d make the outer surface from an offset of the base curve set to the correct height - it will simplify the surface and the top edge will be as clean as the curve.
Making that dish is probably a good case for a loose loft.
Yes the corners had to be tangent to get our desired form for the design, which you’re right does make it tricky!
Very sorry I’m a little confused on the next but you mentioned -
(I’d make the outer surface from an offset of the base curve set to the correct height - it will simplify the surface and the top edge will be as clean as the curve.)
could you please explain a little more, possibly with screenshots?
Your problem is that the shape curve flips directions at the corners. so i would explode that curve and use the railrevolve on the convex curves (purple) using my desired profile. then i would use blend curves with tangency to create the bottom profile for the corner surface (red). then i would use two adjacent surfaces as rails for a sweep2 with the corner (green) and the bottom (red) as profiles, in which i preserve the tangency in the sweep2 options - i need to select rebuild.
you’ll notice that the “crease” gets faded as it goes to the bottom. if you want to control where the crease fades completely, simply divide the profile curve vertically into two segments and repeat the process above
even better if you use network surface
here i used your profile curve to make a rail revolve surface, and split that surface at the corner fillets. then i extracted those edges.
i decided where the transition to a fully convex section will happen vertically (i intersected a plane with the profiles) and made an interpolated curve. i did the same for the bottom endpoints
However I am struggling with the ’ i decided where the transition to a fully convex section will happen vertically (i intersected a plane with the profiles) and made an interpolated curve. i did the same for the bottom endpoints ’
I’ve done interplating curve on surface but not curve on curve if I’m understanding correctly. How do I go about intersecting a plane with the profiles please?
Sorry, I misunderstood! I’ve since intersected a curve across the profiles by using a plane like you said. I’ve used the command network surface and my surface is not looking right. Please see below.
hi B. Network surface creates approximate surfaces based on the curves you input. if you want an exact match between the curves and the surface, your best bet is to use sweep2
so based on your help2 file, here’s what you should do
explode the purpe curve. you should have the corner fillets as separate curves
split the bottom interpolated curve by the profiles. you should get this. (hint: best practice after splitting is to rebuild your curves to be of degree 3 and point count 4)
here is where you need to decide where the transition from a concave curvature to a fully convex one needs to happen.
to explain this a bit, consider how the highlighted curves in the screenshot are curved outwards (sometimes this is subtle)
in any case, use a plane to decide. if the plane is high, the transition happens faster, if the plane is low, it happens more gradually.
and intersect that plane with the corner profiles to create the points for the interpolated curve
create the surfaces of the fillets. we start with this ones because they are all convex. here, use sweep2 with the profiles as rails and the top, mid and bottom curves as profiles
use the corner surface edges as rails and the top, mid, bottom curves as sweep2 profiles. in the dialog, make sure the edges are tangentially continuous (in the edge continuity section)
Thank you very much for your continued help with this build - its greatly appreciated.
I’m still having some trouble with the surface. Please see below screenshot showing 4 versions of the surface. I’ve used your process and changed the intersection line slightly acorss all four as you’ll see the surface becomes steeper and has a bulge where it appears darker in the render. It actually does this on 3 sides. With the slight line change acorss the 4 versions 2 appear alot better but one that is highlighted with the elipse remains.
I’ve compared this newer model with the older loft and the older loft appear smoother in its surface ([please see screenshot below). I don’t suppose you may know any tips with improving the loft at all?
Hi b. Have you checked the file I attached to my previous post?. I think it is as smooth and as exact as you initially wanted, or at least much closer.
In any case, there will always be some compromise. and in this case, if you choose sweep2, you can have control over the vertical profile.
If you choose loft you have more control over the horizontal section.
To get the best of both worlds, you actually need to spend a little bit more time and setting up the curves. You need to decide on questions such as at what angle does the bowp start from the top, how is the transition happening from concave to convex, and so on.
You also need to know a little bit about curve continuity. There are plenty of tutorials online.
So the short answer is that to improve the loft is to improve the curves’ geometry. To improve the curves’ geometry you need to go through an iterative process. And at each curve you need to decide on the direction of the surface particularly at the endpoint of the curve.
Lastly, I will mention that to get the best possible surfaces you also need to learn a little bit about curve optimization, degrees, and so on.
To be able to help you better, I will ask you to list all the geometric design goals for this particular bowl. Perhaps if what you are after is just a smooth look, but you are not particular about the shape (as in it can vary to some degree) then maybe you could use subd
the image on the left is the file i uploaded two posts ago. on the right is a subd generated by quad remesh. see panel on the left for options.
a note on subd: while it is visibly smoother, it is approximative - hence the compromise.
Apologies for the late reply, I was away on holiday.
Subd has worked great - thank you! I really appreciate all your help with this. I will continue to learn more about surface builds as this an area I could use some improvement in!
