Surfaces_Round Tool_Error: Isoparm must be an edge isoparm

[RevinFrost]

Ive been attempting to round the sharp edge between two lofted surfaces.  It worked on one edge once, then never again.  I keep getting "// Error: Isoparm must be an edge isoparm."  I know I'm selecting the abutting edges of the two surfaces, but it doesn't seem to recognize that.  

I attempted to repeat the process using a basic NURBS cylinder only to get the same error.  Tried reinstalling the app entirely, but get the same error.  It now only seems to work when using with basic NURBS cubes.

[Kahylan]

Hi!

The reason this only works on the basic nurbs cube, is that this tool needs a very specific input to work.

It needs exactly two selected isoparms that are at the edge of the surface (meaning they only have a surface patch on one side) and are from two different surfaces (two different surface nodes).

The Nurbs cube is acutally not a cube, but a group with 8 different Nurbs planes that are not connected to each other. This stems from the fact, that Nurbs can't really describe a 90 degree angle that stays 90 degrees if the object is scaled or the cvs of the next Isoparm get moved, because of the way they are calculated. This is why the Nurbs cube works with this tool, but no other Nurbs primitives do.

If you want to round an edge that doesn't fit these conditions you need to use the "Surface-> Insert Isoparms" tool. With the right settings this will create the effect you want.

But I would also like to mention, that Nurbs surfaces aren't really made to create complex shapes with, atleast not in Maya. Why are you using Surfaces instead of Mesh?

I hope it helps!

[RevinFrost]

Thank you for the reply!

-These were two different surface objects (as mentioned in the original post, two lofted surfaces). And I did have the edge isoparms of the two separate surface objects selected.  They were simply butting up against one another, which as I understand is needed for the round tool to work.  

-Yes, I am familiar with the fact that the NURBS cube is actually made up of several planes and that curves are the core function of any NURBS object.  But your statement implies that the round tool was designed by Autodesk for one and only one process.  To round the corners of the cube object.  My opinion is that this is not accurate.  Unless they have stripped its functionality in recent iterations of the app over the last 15 years.   I have seen many, many artists online that successfully apply the round tool to objects like cylinders and other more complex shapes like the one I am using.  I've seen entire super-car models built with NURBS before being converted to poly for end use.

And I did successfully use the round tool on THIS object earlier in the day before reverting to an earlier version of the model.  So I have no doubt it's capable of working for this.  

-My real issue I'm hooping to find some help with is the error I reported at the beginning.  

Why it's not accepting the two edge isoparms I'm selecting as proper edges.  

Given everything I've tried I feel like this is a problem with the app (corrupted preference file maybe), but was hoping I was simply missing a setting with the selection tool or something.  When I select the two edge lines, the color looks to be part blue and part yellow... like its indicating it is only selecting one of them.  When I select a non-edge isoparm, its a sharper shade of yellow.  Please see picture uploads for example.  

 

 

 

 

[Kahylan]

"But your statement implies that the round tool was designed by Autodesk for one and only one process. To round the corners of the cube object."

I'm sorry, but could you point me to the part of my reply where I implied that? Because all I said, is that his round tool only work with the cube PRIMITIVE because it is the only PRIMITIVE that has separated nurbs surfaces in it. Which I mentioned because of your comment :

"I attempted to repeat the process using a basic NURBS cylinder only to get the same error. " ... "It now only seems to work when using with basic NURBS cubes."
The NURBS cylinder comes in one single node, the NURBS cube doesn't. It sounds pretty much like you were confused about why there is a difference, you have to admit that.

But I'll admit, I accidentally overread that you were aware that it needs to be two separate objects, the quite vague description about what you were doing with cylinders and cubes kind of overshadowed that...

So you mentioned, that this worked in an earlier version of the model, but it doesn't now. Do you know what the difference between the model then and the model now might could be?

Have you introduced any history nodes?

Have you comined some of the surfaces?

Have you added the shape of one surface under the translate of another?

Have you tried deleting history before running the round command? Maybe the loft surface history nodes are causing a problem.

What edge did you previously successfully run the command on and what may be different to the one you are trying it on now?

Also, could you upload your file as a zipped .ma and tell me the indexes of the isoparms you want to round?

If it really is a corruption problem with your app or prefs, I should be able to do it without a problem.

[RevinFrost · Accepted solution]

So... I chatted with one of the Autodesk experts and it looks like Viewport 2.0 may have difficulty with isoparm edge selection.  Soon as I switched over to Legacy Viewport, I was able to select the edges it needed and the round tool worked as expected.  Maybe it was just something with my system, but hopefully they will look further into it.