How do I remake these ornamental elements?


Customer is wanting to recreate this pediment for a new door adjacent to this one. How would you go about duplicating these rosettes/onlays?
3d scanner? Photogrammetry? Lidar? Urethane mold?

Any input/suggestions are would be greatly appreciated!

If the intent is to recast then a Urethane mold seems like the way to go.

A scan will work here too, but would be used as a background while you rebuild using SubD, the mesh out of the point cloud would be OK, but probably not ideal.

If you have a mac the photogrammetry is an option, once again the mesh won’t be high quality. Rhino 8 (Mac) Feature: ObjectCaptureFromPhotos

Recasting is the most efficient way, I believe, although not cost-effective. My boss wants to see if we can mill them from a 3d model, which is where I come in. I’m not to keen on having to create a 3d model and then trying to mill these on our 2.5-axis CNC.

Agreed. The creation of 3-4 unique models, then smoothing after the CNC operation sounds way less cost-effective than a mold, depending on your SubD modeling skills and router bits.

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2022-01-25 12_43_50-pediment (2).jpg ‎- Photos
Any recommendations how you would go about modeling this? It’s a 4" square rosette. Boss wants me to try to 3d model it. It doesn’t have to be exact, but as close to this design as possible. Unfortunately, this is the best picture I have to go off of, without going back out to the site to take better pictures. I’m stuck on Rhino 6, so I don’t have any subD, either.

Hello- it looks like there are relatively few elements to make - everything is a mirror or rotated copy of this bit

image

That does not make it easy , but perhaps less daunting. My guess is some careful curve drawing and some Sweep2 or NetworkSrfs may be the thing.
The center is a revolved surface.

-Pascal

Hi. I usually start by aligning the reference image in photoshop or right inside Rhino. This rosette is extremely simple for modeling. You don’t need any SubD here. Just make 1/8 of the rosette with normal surface modeling, mirror it and copy around the center. If you’ll need help send me a PM.
Andrew.

Hello Andrew,

I appreciate that you are an expert modeler but for someone like me with much more modest modeling skills, modeling this rosette looks like it would be a challenge. Yes, I think like you suggest I would take the ( in this case greevedo may be fortunate to be able to get RAW data - maybe ask the customer ? - if the picture was taken with a camera) image into an editing program or two (i.e. vector) to maximize the ease of working with it in Rhino e.g. if I could scale the image 2D to the size I want to model it, for me that would be great.

But the actual surface modeling appears to be challenging.
Also, ( and maybe I missed this or it is implied - once you have your segment modeled you could do a polar array or I think it might be worth it to model 1/2 of the object and then just mirror this as I think Pascal is suggesting.)

Thank you,

Andy

p.s. If I am misguided in the use of a polar array in this case please let me know.

If you could improve the image significantly and then bring it into Rhino and try using the Plug -in Vectorize ; given you get a good result from that then I imagine I would have the curves or enough of them to work with and then the surface modeling might be much more manageable for me.

Hi Andy. When I say that this modeling task is really easy, I just don’t want a colleague to spend a lot of time on unnecessary steps. For example, to find a more suitable image or to vectorize it. You can work with basic tools directly on the image that I processed and sent here. It just needs to be brought into Rhino as a reference image (_Picture), scaled to the desired size, transferred to any other layer except the default one and locked. Now you have to create a dozen vectors and use them to create surfaces on the area (1/8) highlighted in red. Here you can use the tools offered by Pascal, for example. Next, you mirror ( _Mirror) the generated surfaces and get 1/4 of the required model. Next, you copy the 1/4th model around the center (_ArrayPolar). That’s it.

PS: I’m still ready to help. Today I work at the computer all day. I am at your service, if needed, with the help of Team Weaver and any messengers.

Andrew.

Hello Andrew,

Thank you so much for the offer. I appreciate it. Maybe greevedogg will post the model he develops.

Thank you,

Andy

Well, I was able to model the small 2" dia. rosettes and milled them out of 60 lb architectural foam. They came out pretty good. The additional elements–we ended up making silicone molds and casting them. I think if push came to shove, I could have modeled these, but it was just more efficient to mold them. Thanks for all the input though!

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