scan data to form body - car lip - fails thickening crashign fusion what am i doing wrong

[OmegaDreams]

so im modelling this lip and trying to get it to scale.   to slice up at the end for 3d printing 5mm thick and then add bosses for screws to bolt together.  as a base for a form mold .. it needs to be accurate at the top edges to the mesh  . and the rest is custom to match . ( scan data was not perfect and i dont have a new model lexy RCF  body to reference. )

so i used forms and made teh form shape  and it looks good enough ( im no pro but imlearning and getting better every time  but when i go to thicken this in forms or in surfaces  to get 5mm plastic to add bosses to  it errors out and often times c rashes fusion 

is there a workaround or a way to make this better  so it works ?
each slice if i can get it to thicken im fine .. but its always getting interesecting faces .. 
help ?

[TrippyLighting · Accepted solution]

I've modified your T-Spline. I removed all N-Gons and created a better, more even edge flow. 

Always check your mesh in Box View mode. When making modifications in smooth-view mode, be gentle and always check back in box-view mode. 

This thickens to 5 mm, although that already creates "strange" greases that look like self-intersections.

3-4mm is a better range for thickening, or you need to slightly modify the T-Spline to make radii bigger.

[OmegaDreams]

looks great thank you but i also need to learn how and where i went wrong..  
5mm is what i need for thick but 4 can work ..  but also need to slice it up into printable parts and add screw bosses for assembly
( i can handle that if it doenst crash fusion )

[TrippyLighting]

The only way to learn it is by doing. Compare the two meshes and see if you can edit yours to look like mine.

I use the insert point tool often to insert new edge loops. Sometimes I use the weld vertices tool.

Some of your quad looking faces have an additional vertex somewhere along an open edge. you can just select and delete it.

[OmegaDreams]

actually the lip you made was wayy to protruded adn no longer follwos the body lines of the original mating surfaces. 
so when i made the minor change to 'suck back ' the lip to match the key areas of the scan  it now fails again  even at -3mm

the geo does look cleaner which is great..  but it stillmakes fusion explode.. 
the errors cause fusion to halt .. and sometimes crash .. so my next step is to rebuilt the os. jsut in case .  because  mys system attempted to encrypt my drives and lock me out jsut now.  .. 

I managed to tweak it a little and get it close and had to result to 2.1mm to get it to work . but blender does a better job of thickening surfaces..  one would think fusion should 'merge those intersecting faces' and shorten the inside radius as needed to make its math work ..  heres the sliced up result 
thanks !

[TrippyLighting]

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@OmegaDreams wrote:

...but blender does a better job of thickening surfaces.. 

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I have used Blender for 18 years and have used it to clean up some of this geometry.

It can all be done in Fusion, just not nearly as quickly. Edge slide and vertex slide (vertex slide is not possible in Fusion) are much faster than in Fusion )key combo "gg". I can flatten with the loop tools with more options than in Fuiosn, I have proper snapping options to align vertices etc.

If you want to compare how Blender thickens surfaces, you'll have to compare it with how Fusion thickens in the Form environment.  They produce exactly the same result because you are offsetting the control cage. In a model such as yours that will lead to uneven thickness.

When thickening in the surface tab, you are thickening the NURBS geometry created when finishing the form. There is no equivalent in Blender, because Blender works with meshes only.

Fusion can trim otherwise self-intersecting geometry when you use analytical surfaces/geometry. However, that does not work with NURBS geometry, particularly geometry created from T-splines.