Maya Bevel Behaviour

[Anonymous]

Hi

I am new to 3D modelling and am trialing Maya 2016. I am just playing around trying to get a handle on the basics but I have hit a wall with the bevel tool. I have Googled in the hope of finding an explanation of what I am experiencing but the only forum entries I can find just mention that the Maya bevel tool can be problematic. I can't seem to find anything directly related to my issue. Apolgies if this has been answered elsewhere.

I create a simple polygon cube then select an edge and bevel it. I then separately select another edge on the opposite side of the face and bevel that too. I now have two seperate bevels (polybevel1 and polybevel2).

When I delete polybevel2 I am left with polybevel1 (as expected) but if I delete polybevel1 instead (with the expectation of leaving polybevel2 intact) polybevel 2 suddenly moves to another edge entirely!

Could someone please explain if this is normal behavoir and if so why?

I notice in the node editor that the output of polybevel1 is connected to the input of polybevel2 so I am assumung that polybevel2 is inheriting something from polybevel1 and that when it gets deleted it throws everything off. Whatever is going on seems very unituitive to me but I would really like to understand this behaviour.

Many thanks if you can help

James

[Anonymous]

This is quite typical Maya behaviour.

Look at it this way, a box has 12 edges. Maya thinks of these as Edge #1, Edge #2, etc.

Now I bevel edge #5, and I have 3 more edges than before, Maya will now renumber any edges that come after edge #5.

Then you move onto bevelling edge #8, now known as edge #11. That works out fine, until you manipulate the original Polybevel1, which changes the number of edges, and suddenly your Polybevel2 is applied to another position. I'm afraid that in addition to this, if the number is now an edge that no longer exists, Maya will flat out guess where to apply the bevel. But the above is one of the reasons going back and forth and editing history states is a very reliable way to crash Maya.

I've made a habit of keeping my left hand fingers near Shift+Alt+D for delete history while modelling. This will collapse the history stack and put the changes permanently into the mesh. It's safe to keep quite a few history states, as long as you don't go back and edit them, but I recommend deleting history as soon as you're happy with the outcome of an action.

You don't want to do it while rigging and skinning.

ps: Most probably Maya is only numbering vertices and identifying edges by which vertices they connect, but the result is the same.

[Anonymous]

Thanks kristine

That makes things much clearer now. I just wasn't considering the fact that Bevel is actually creating more edges and that they all need accounting for. I can now see the need for taking quite a measured approach to modelling - ie. attempting to get each element correct before moving on rather than get them roughly OK with a view to correcting later.

It's funny you mentioned Maya crashing because that was exactly what hapenned as I was playing around deleting nodes whilst trying to work this out!

Thanks again

James

[Anonymous]

Poking the nodes is the best way to make Maya crash, but you also kind of need to do it to get things done later on. Anything to do with shaders or rigging relies heavily on plugging nodes into each other, often things that were not designed to be so. One example I have learned in school is to use the colour Blend node's RGB output to calculate XYZ rotation, because they're all just data being piped around. It's great. Maya crashes a lot, for many reasons, in many ways, no matter who you are.

Maya's node-based method is famously opposite of 3dsmax where that bevel could be a layer modifier, but I think you'd have the same problem in the long run. 3dsmax is a little more stable and versatile for modelling iirc.

What I would do would be to just accept the first bevel if I really liked the second... keep it around for later, maybe merge the 2 edges back up. Moving geometry around with move, scale and rotate doesn't cause any renumbering (but depends on those numbers too of course). It can be a very organic process, especially if you are as analytical as you are about what things are doing. And uh, save often.