MASH curve node and normals

[Steve Davy]

Question for Ian if he's looking...

I'm hoping to use the MASH curve node to place stitching on a shoe, pretty much exactly in the way that's demoed in the rivets tutorial, i.e. convert poly edges to curves and send instances down them.

The problem I am having is that my stitching is not perfectly following the surface normals all the way along the curve, rotating incrementally from the curve start where it's very slightly off, to the end where it's oriented correctly.

The tutorial doesn't mention normals and the rivets all appear oriented correctly, so I'm assuming this is what should happen.

I've looked at the surface normals to see if they are off but everything appears to be OK. Also tried using an aim curve but this doesn't seem to have any effect at all no matter where I place it or how I scale it.

Any suggestions? I'm in Maya 2018.

[Ian Waters]

Hey Steve,

When using the Aim curve, turn up the Roll to 1.0. Can’t remember why that is!?

MASH doesn't actually use the Curve normals to calculate rotation anymore, it caused too much flipping and odd twisting - and as there’s no way to edit these normals in Maya (that I know of anyway!) we switched to method of generating our own twist free normals (99.9% of the time :) - however, this does cause some drift, which is what you’re seeing. Two ways forward, use an Aim curve, or open Extra Attributes, and turn on the Legacy 2016 switch, which is left ‘public’ for this reason.

Hope that helps,

Ian

_ Ian Waters Lead Developer Mainframe 82 Silk Street Manchester M4 6BJ 0161 205 4763 mainframe.co.uk @ianwaters

-- 
You received this message because you are subscribed to the Google Groups "maya_he3d" group.
To unsubscribe from this group and stop receiving emails from it, send an email to maya_he3d+...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Steve Davy]

Aha. Setting the roll to 10 worked perfectly. Thanks Ian!

---

From: maya...@googlegroups.com <maya...@googlegroups.com> on behalf of Ian Waters <water...@gmail.com>
Sent: Wednesday, April 4, 2018 12:49 AM
To: maya...@googlegroups.com
Subject: Re: [maya_he3d] MASH curve node and normals

 

[Steve Davy]

OK, so having solved that problem (awesome), one of the things we are maybe hoping to do is animate the stitches appearing along these curves.

This kinda works using the step strength on the curve node, but I'm noticing that every few frames one of the stitches pops out of alignment on the curve.

I'll try attaching an image but this list seems to strip attachments (if any of the admins are watching and know how to fix this please do -- I'm an admin but keep forgetting to look and can't right now).

Is there anything I can do to fix this?

Thanks again.

---

From: maya...@googlegroups.com <maya...@googlegroups.com> on behalf of Ian Waters <water...@gmail.com>
Sent: Wednesday, April 4, 2018 12:49 AM
To: maya...@googlegroups.com
Subject: Re: [maya_he3d] MASH curve node and normals

 

[Ian Waters]

Hard to tell - can you send me a scene?

Is animation speed turned to 0? Perhaps try disconnecting the time attribute?

Ta,

Ian

<MASH_Step_Strength_Issue.jpg>

[Ian Waters]

Oh!

I just thought (I’ve been off the tools too long ;), it will be because the step strength is also running the rotation down.

You should probably use a Visibility node or Offset (with scale) node to achieve this effect.

Strength on the Curve node affects the position and rotation, it doesn’t touch scale.

Best,

Ian

_ Ian Waters Lead Developer Mainframe 82 Silk Street Manchester M4 6BJ 0161 205 4763 mainframe.co.uk @ianwaters

On 4 Apr 2018, at 19:10, Steve Davy <stevi...@hotmail.com> wrote:

<MASH_Step_Strength_Issue.jpg>

[Steve Davy]

OK I'll give that a shot. Thanks again.

---

From: maya...@googlegroups.com <maya...@googlegroups.com> on behalf of Ian Waters <water...@gmail.com>

Sent: Thursday, April 5, 2018 12:54 AM

[Steve Davy]

Hi Ian,

Of course that makes sense about the rotation now...

Tried your suggestions with both visibility and offset, but a falloff object on either node doesn't seem to respect the Add mode as I run it along the curve. Should this work?

---

From: maya...@googlegroups.com <maya...@googlegroups.com> on behalf of Ian Waters <water...@gmail.com>

Sent: Thursday, April 5, 2018 12:54 AM

[Steve Davy]

Ah, never mind -- just watched your old tutorial and learned I have to cache it.

Never realized that and explains why I've always found the falloffs to be so unpredictable in Add or Remove mode!

---

From: maya...@googlegroups.com <maya...@googlegroups.com> on behalf of Steve Davy <stevi...@hotmail.com>
Sent: Friday, April 6, 2018 12:59 PM

[Ian Waters]

Yeah that’s effectively a simulation and thus needs caching (as it relies on previously accumulated data).

Glad you got it working,