What's the best way to create the glass bowl for this street light?

@Quadhurst and I have been having trouble creating this model of a GEC streetlamp canopy and bowl.


GEC Z481 canopy JWM 2.skp (1.0 MB)
Using FollowMe with the path and profile shown to create it, and then using Select All, and Intersect Faces/With Selection, makes a mess of the corners, which should be rounded in both plan and elevation.

However, it does clean up better than our original attempts, so perhaps we can’t do much better?

Can the profile or path be modified in some way to get a better approximation of the thick glass shape in the photo? If so, how?

Or how else can one draw it?

hello, the follow me tool will work best if you use the narrowest part as a guide.
see this file :
GEC Z481 canopy JWM 3.skp (1.0 MB)

also remember that with symetrical objects like this one, it is better to make a component out of half of it, and mirror it

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That certainly looks better - thank you.

When I make it transparent, I see a few stray lines inside, but that’s easily fixed.



GEC Z481 canopy JWM 3.skp (1.3 MB)

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Well, it seems we aren’t quite there yet.

Talking to my collaborator, who is just back from a holiday, it seems that the glass bowl is only a thin one maybe 1/8" thickness only.

And there is a separate flat plastic ridged rectangular plate on each long flat face of the bowl, and possibly another on the (nearly) flat bottom, to diffuse the light.

I’ve had another go at it, using a 1/8" thick profile, and a path which has small radius corners, on the inside of the FollowMe path.

Looks like this:

GEC Z9481 canopy lower bowl 8 JWM Aug.skp (1.3 MB)

But that seems to make the upper outer part of the bowl have too large a radius which fits very poorly into the canopy/top.

Any further ideas on how better to draw this? From previous experience, it seem that using a more curve-ended outer path for FollowMe would leave all sorts of intersections and overlaps at the corners.

And a separate issue - any idea why the translucent material is showing in distinct quadrants?

The reason the texture looks odd is that it is like any projected texture, it is using an image and is breaking it up. You’d probably do better with a solid colour made translucent.

I would use curviloft or extrusion tools for the bowl shape, and either do it twice or thicken with JPP.

Curviloft Light

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@Box - sound and helpful advice. Thank you.

IIIRC I used a built in glass texture, but might try plain white or light grey colour instead.

Will try Curviloft.

Yes you did, but they are image based.

Ah. That would explain it.

Had a play with your model last night. Pretty much went with the same approach as Box. Made two versions. One I kept the shape of your original lens and I remodeled the inner edge of the top to match the lens. Second one I changed the contour of the lens to match the contour of the top. Just scaled down copies of each lens to create the inner diffuser lens. Posting the model for you to check out , use as is or change as you like.GEC streetlamp_new.skp (1.6 MB)

Thank you very much. Both you and Box have been very helpful.

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John , I wasn’t sure how you intended to use the light ( raw SU views or rendering use ). I fixed things up so the various parts are solid components. If you want to lighten them up some you can always eliminate the inner side of the lenses. The inner lens I painted with the stock “corrugated glass” texture. Used Fredo’s ThruPaint. It makes it easy to scale and position the texture.

Eventually, I think Andrew (@Quadhurst on the forum) will want to render the various models we’ve been working on for a book he’s been commissioned to write.

Always good to have solid objects when possible.