T-Splines-trimus

1、T-Splines-trimusOrganic Modeling for Industrial Design with T-Splines and Rhino ?4, using the tsSkincommandCase studyProduct development, and in particular products claiming an ergonomic benefit, are often derived from working with physical models.In this case, the issue was an ergonomic mouse that

2、Ive developed based on medical research. Shapefinding started with clay models and I knew early on I was aiming for an organic shape. Model-ing this with NURBS would be very tedious.Background: Preparation for input curves Moving over to a more firm material- foamed polyurethane - the shapeof the mo

3、use started to settle.To prepare for the 3D modeling, Itraced lines on the model to markenough curves to define the shape.These curves would later be usedfor building the surfaces.Preparation: Using a digitizer to capture curves Using a digitizer arm, the curves traced on the physical modelare easil

4、y transferred into NURBS curves in Rhino? 4.Preparation: Refining the curve layoutTracing with a digitizer will not produce perfect results, and most often the output curves will need to be tended to.The raw curves were manipulated, rebuilt and somewhat reorganized in order to match up and provide b

5、etter input for the T-Splines tsSkin command.I also added additional curves using the InterpCrv com-mand.T-Splines STEP 1Select input curves Select all the curves defining theshape and run the tsSkin com-mand.T-Splines STEP 2Curve intersection The tsSkin command divides the curve network according t

6、o the tolerance set. A larger tolerance value will regard curves that are farther apart as touching. Keep your eye on the numbers. They will tell you how many curve divisions are intersecting a certain cross-ing. If the value is lower than the actual number ofcurve ends meeting, the tolerance can be

7、 increased.For best results, see to it that the curves really are touching before skinning, and use a low tolerance.T-Splines STEP 3Topology - the distribution of the surface When previewing the topology, simple surfaces aregenerated to visualize and provide an interface forchanging the distribution

8、 of the surface. This is basical-ly just a way of telling the plugin where you would likesurfaces, and where you would like openings/holes.In my case, I wanted a closed surface, so by clickingthe surrounding edges I turned on all faces.T-Splines STEP 4Adjusting the fitting With fitting turned on, th

9、ere are a few ways of adjust-ing the behaviour of the surface. Without knowing the exact mechanism behind how these work, one caneasily tweak by trial and error using the preview but-ton.Here Im adjusting a parameter making the surfaceflow tighter along the original curves.Manual tweakingCompared to

10、 working with NURBS patches, the T-Spline remains a single editable surface, and even better, will have up to 70% less control points situated only where needed. This makes it a charm when it comes to tweaking the surface to adjust the shape.If more control is needed, extra points can be added using

11、 tsInsertPoint. In order to sim-plify the shape, points can be removed with ts-Delete.T-Splines are converted into NURBS patchwork After converting to NURBS, the curvature continu-ity between patches is preserved.Post work: adding details With the overall shape readily modeled in T-Splines, details are added using any given NURBS technique.Render and physical model side by sidecontact information:bjornsyse.sehttp:/www.syse.se/