FilletSrf or Sweep what would be best here?


attached an object to have a 50mm rad fillet around the most part then an increasing fillet as indicated by the suggestive black lines for the latter part.

It continues past the straight line ‘A’ but for simplicity of this post I have trimmed it here. The back has a shallow open arc.

What would be best, construct it with profiles or attempt fillet ?

My filleting to the blue surface failed in one hit with the pick only selecting a part of the surface yet they are joined.

What does one need to do to surfaces to get them to all be pickable as one unit ?

I tried for MergeSrf but it failed. Could someone explain why.

I also tried JoinEdge which fused one edge together yet it still appears to have a gap…(its under the green 30mm rad)

two seams were filleted but as you can see they filleted in a sort of mirror fashion and did a part that wasnt in need of filleting ! (orange and green)

The surfaces were formed from a sphere, a sweep of a circle from the sphere and other sewwp to rails then intersected and trimmed to intersects then trimmed to the blue skin.

At least now it shouldnt try to fillet things under the skin ! Was that necessary or wasted effort ?

Does it need a mergeSrf to fillet or should joined surfaces be ok ?

Cant find anything in the training guides on FilletSrf and requirements.

The fillets are all tangent from the surfaces and no S bends as such.

If I use the lines drawn tangent to the surface, what is best way to tweak these curves ‘as one unit’ to get a flowing shape ?


FilletOrSweep.3dm (506.3 KB)



It’s really clear that you are in way over your head. The best advice I can give you is to order this tutorial in PDF and complete the model detailed within. It’s an interesting and advanced project.


Thanks for the link. I really look fwd to that as well now.
I will be revisiting Level 1 and working Level 2 and also now this, and look fwd to doing so.
I have no chance to do so until I finish the job I have been working on flat out for months now, and this structure requiring fillet or sweep was the last item before it is sent off, there is no time available for escape and spending time on these, a catch22, I didnt take it on declaring myself 100% knowledgeable, I was needed, I also needed the money and had no choice. I would dearly love to take time out as the result would no doubt speed things up but that is not an option. I have done the job so I am not over my head as such on what I needed for it. If one were to see what I had to cope with research wise then I would be awarded a medal !

As for this structure, FilletSrf is not suitable now as further data shows a tangential straight line slope down to the radiused curves so I might as well construct the shape for thats what it needs. so Sweep2 will be used. It would have been the variable fillet srf to finish the job. I might go with variable having constructed the straight line slopes.

If someone would be so kind as to answer what the surfaces require to be pickable as one unit and why MergeSrf refuses to work I would be grateful. Yes the answer no doubt lies in the tutorial but I have hours left to get this off now.

Then I have a PC to rebuild !




This is the approach I would typically take for a form like this. This was done in a bit of a rush but hopefully you will find it helpful.

MergeSrf does not work with trimmed surfaces.

Your attempts at filleting these surfaces is pretty typical approach for solid modelers. It’s extremely difficult to do with nurbs surfaces. You would be better off trimming the surfaces with curves then surf blending them together. I prefer the patch method.

FilletOrSweep_Rebuilt.3dm (622.9 KB)


Oh wow :slight_smile: :slight_smile:
I wish I could see a video of this being done. You have captured the tangent slopes and fillet, its beautiful :slight_smile:
I dont quit follow the text, you say I need to trim the surfaces with curves then surf blend them together, and you prefer patch.

Is this (with patch) how this was done ? It almost reads as if you did this a very different way.

trimming surface with curves you say.

I had plans to place in tangent lines all the way round as I had started to then establish curve for their top ends and use that to trim surface then do a sweep to the profiles using that as rail and another at base after creating the radiused curves on the tangent lines to get my profiles…

Is this radiused base a fillet or sweep2 or ? I am not sure how you did this unless it was as just described.

I can use that to finish the job, or so I thought, it doesnt fit instantly with my base skin, so I have orient3pt yours to mine as it was at a slight difference. then rotated with axis along lower edge the top leftcorner down, but the back needs extending a bit, so I reached for extendSrf but whilst I can extend mine, it doesnt allow me to pick yours. I can’t extend it to trim it to match mine.

Why wont ExtendSrf select it ?

Also in rendered view my surfaces are grey but this is white with some reflectance of black lines. I cant see how to alter it despite looking in properties.

I like the orange jpg, I havent even explored the rendering lighting etc but will do when need arises. Just for the record, what did you use to get that effect ? Just inquisitive . I only have Rhino V5, no flamingo etc.




By patches I mean multiple untrimmed surfaces (with a few exceptions to guide other surfaces) NOT the patch command. They can be easily point edited and matched.

I have auxpecker for rhino it’s a free plug in it works with Rhino’s Render display mode. No need for renders just screen caps with auxpeckers material library.

You might try and use SurfUntrim to match up the large trimmed surface to your existing model. Extend surface won’t work with trimmed surfaces.

I had to rebuild all your surfaces. It would have taken me forever to reverse engineer what you had made with the patch method. I tried to make as many of the surfaces with simple degree 3 - 4 point curves. I did cut some corners and use some existing surfaces trimmed with Surf Split at Isocurve. I used Sweep 2 for the large curved surfaces.

The point of this was to show you the benefits of simple flowing topology. Built from simple curves. It all starts with the curves. These videos are good example of the commands and methods I use. You don’t need VSR to do this but it sure helps and speeds things up.


Thanks for the talk through.
I am going to follow your every word and work this as a good exercise, as you said its not easy for solid modellers. How many years experience have you at this ? I shall watch videos and then tackle my shape.

Meanwhile so as to get this beautiful result onto my model, I looked for SurfUntrim but its not in V5

Tried SrfUntrim not there

Tried UntrimAll and it fails

Tried Untrim and at prompt to select an edge I am still unable to select an edge of this.

I draw a square surface and then a line across one side and with trim command chop one piece off.

I am able to use extendSrf on all four sides of the surface, so it worked on the trimmed edge. Not sure what you mean.

Still unsure why this shows as white amidst my grey surfaces in Rendered view.

Managed to join it to my object and al went white…eeek…then changed material to default and all is grey, I could see Auxpecker reflected in the object !

I am able to select edges on it, but extending surface etc is a no go.