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Unable to thicken surface models containing blends

Unable to thicken surface models containing blends

Unable to thicken surface models containing blends

(OP)
Hi,

Unable to thicken surface models containing blends.

Please forgive the long explanation of my problem but it’s the only way I can describe it..

I have been using GSD to create some 3D models that will be used to create plastic panels for a scooter. I am fairly proficient at using GSD workbench for body in white and mechanical parts, but on the side I have starting to dable with Class A surfacing. I appreciate GSD is not really the tool to use (don’t have access to Icem, freestyle WB or anything like that) but I have managed to produce some models with complete curvature continuity.

I am struggling to thicken some of the parts/surfaces. Mainly on small edges where I have created blends. I have been creating small gaps between the 2 mating surfaces and then using blend to get my smooth edges. As you can appreciate this is really difficult/time consuming, but my main trouble is when trying to thicken! – it won’t. Tried all workaround like using bigger blends, closing/shelling, smaller thicken sizes and thickening in both directions.

The only way round this is to use fillet command (with conic option). I would like to use this for the small edges on my parts but do not want to compromise on the quality (as radius/conic will not produce curvature continuity).

For small edge radiuses would you really notice any difference between a small (3mm) blended edge and a conic fillet?

Thanks

RE: Unable to thicken surface models containing blends

Hi thecadman3,

I have had problems such as the one you described (not being able to apply thickness to a surface) and what I did was to join surfaces as a I felt, and trying to thicken them. It is a recursive approach but it can work pretty well if you "guess" where the problematic areas are.

Hope this kind of approach will help you.

Best of luck!

RE: Unable to thicken surface models containing blends

(OP)
Yes helps thanks

Do you mean do this only to highlight the problimatic areas? or create a multi thickened part from multi joined surfaces?

RE: Unable to thicken surface models containing blends

It helps isolate the problematic area...
Not very professional, but it should work. This method is tried and tested by me roll1

RE: Unable to thicken surface models containing blends

(OP)
Definitly going to try this option....

Does anybody know if a small radius (with conic option set to 0.5) would be noticably different than using a curvature continuity blend? on the actual phyisical part.

RE: Unable to thicken surface models containing blends

Have you done a surfacic analysis of the surface? checked minimum radius?

RE: Unable to thicken surface models containing blends

(OP)
I have only looked at surfacic analysis to check any inflections so never used the radius analysis! the min is 1.15 on a blend. Im trying to thicken to 3mm.. could this be part of the problem? need to understand this

RE: Unable to thicken surface models containing blends

As you spotted, if your part thickness is 3mm then your minimum rads need to be at least 3mm otherwise it won't offset.

I get this lots with automotive bumpers where the Styled surface rads are less that the material thickness. In this case there's no option but to model the A and B surfaces seperately in GSD, and then create a closed surace in GSD and then finally a Solid in Part Design. This is what I do on 99% of the mouldings I do. It's far more time consuming that modelling one side in GSD and then using a thick surface but it's flexible and I can vary the internal and external radii to suit my requirements.

The A surface rads are usually fixed by Styling and are conic generated in ICEM or ALIAS but for the B surface I'll just stick a plain radius in that gives me the material thickness that I need and the fact that it isn't curvature matched doesn't matter as it's not seen. For A surface rads less than 3mm, you'd be hard pressed to tell the difference between a conic and a true rad but I normally use a 0.6 conic for rads between 1.3 and 3mm, and use a plan rad for anything less than 1.5mm.

RE: Unable to thicken surface models containing blends

(OP)
Thanks for that..

I am doing just that for one of my parts. Although its a B surface it may be used to cut male Bucks for Carbon fibre parts.

I looked into the conic rad on youtube, and between them and a small blend, the differance is small. By adjusting the paramater (like you said 0.6) you can almost get curvature contiunuoity.

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