Finally found a proper Tsplines-Rhino-Modo pipeline to do 3D-upholstery/sofa/chair designs (remember you never get the inflated sofa look in Rhino working) - thank to Tsplines’ Retopo-Snap.
hope that helps! 
Process is described at the current video location
Not sure I understand why all the steps. TSplines is capable of doing the edge piping and easily creating a puffy look from just pulling a few edge splines. Took maybe all of 10 minutes to model while staying entirely within TSplines.
Box mode
Some careful lassooing of spline groups permit resizing the upholstery to required targets. It’s preferable to selecting the whole global object for scaling. The latter would start messing with mitre angles.
Thanks a lot @CarterTG for showing me your approach. I was kind of cool with SubD modelling in Modo http://bit.ly/1Pof6X3 but didn’t really get this working in furniture design. It was always not my kind of style to tweak the designs that it would match the looks.
And this is the actual point. My approach is kind of the missing connection between NURBS and SubDs. You can draft a overall design with curves in Rhino, set the overall dimensions and do the construction of mechanisms and finally take the couch part or any organic looking part and take the NURBS as a ‘magnetic’ background object or 3D template to proceed on the final shaping via a polymodeler or in your case withing Tsplines itselft. And I would take the final shape to test certain piping profiles in Rhino or later (when I get a grip on that) in Modo.
Maybe when my skills are getting better I finally drop Rhino or use it only for the sideview outlines but being able to use both approaches makes it far more attractive for a start.
Hey @CarterTG can you pls explain to me a a “seashell” condition which makes it impossible to smooth the surface?
I want to edit my surface which is no problem in Modo but in Tsplines it says ‘the mesh is invalid’
Here is a common thread on Tsplines forums but the guys act so slow on issues…
http://www.tsplines.com/forum/viewtopic.php?f=9&t=63292&p=78394&hilit=invalid+mesh#p78394
Thanks a lot for clarifying this! Hannes
Back when I learned T-Splines through all the free webinars, there were always a repeated (and perhaps unwritten) collection of best-practice procedures to follow. One thing I rarely if ever saw the gurus I learned from was the practice of modeling by deleting individual splines to hone fine-detail. T-Splines ALLOWS this (to some extent, IMO)… and certainly the namesake “T-Splines” is in reference to the “T” juncture that the mathematics at its core permits.
Nevertheless, I would personally classify the creation of 3-sided & 5-sided faces as one of those things-you’re-allowed-to-create-but-shouldn’t to avoid headaches down the road.
In your image, you already have that first face where you erased a spline giving a 6-sided face. T-Splines typically tolerates bad geometry as long as it occurs rarely – by that, I mean usually 2-3 faces away from any other modeling goofs. Instead, HERE you’re looking to delete a spline on an adjacent touching face to the first one. Whatever T-Splines calls this, I have no idea as it’s not the way I model and thus stuff I don’t see.
If T-Splines popped up a warning about a “seashell”, all it took was a Google Search with “tsplines seashell” to land on this thread from 2011 where Tom took time to post a video explanation:
http://www.tsplines.com/forum/viewtopic.php?f=9&t=32884
@CarterTG thanks for taking you time for clarifying . so good to know about this know. I think with time I hope to get the same level as you to manage everything in Tsplines. Like it more as everything in one tool. Thanks again! Highly appreciated!