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Quading sphere end onto shrink wrap


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I have used a sphere for the basis of a shoulder. On the whole, the sphere has been tweaked apart from the perfectly spherical top. The very top of the sphere is made of triangles; I want to convert the triangles to quads. I have separated the top of the sphere, replaced the triangles with quads and tried shrink wrapping my quadded sphere onto a perfect sphere made of triangles. Except, my quadded sphere is always on the flat side and not perfectly rounded. I've seen this done in a tutorial, although they are using a half-sphere end. It looked like a simple operation, but I have been trying for more than a day but can't get it to work on my full 360 degrees of triangles (at the end of the sphere). In the tutorial, they used a brush to smooth the pints of the quadded sphere along the shrink-wrapped object – only when I do this, the points all completely flatten out. Any help or pointers would be much appreciated. Thank you.

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Some pictures, or better still, the file would be helpful here... we will invariably need to see the wider context of the model in order to properly advise.

 

However there are still some things to say in the absence of those...

 

1. The even-ness of your topology will govern how rounded a silhouette can be achieved when shrink-wrapping.

2. It may have been a better technique to spherize your topology while it was still a quadded spheroid to save you the projection / shrink-wrap stage altogether.

3. The correct form to shrink-wrap onto is not necessarily a tri-sphere.

 

If I had the scene file I could tell you what to do to fix it...

 

CBR

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OK, well my first instinct here would be to quadrify it like so...

 

image.thumb.png.e664bd3dba43f8a4762426c68990df4f.pngimage.thumb.png.317befb450dda87978846e85af302562.png  

 

Now that looks near-as-dammit spherical to me on the top part, and subdivides suitably well, but technically it is not an exact spheroid because I have completely removed the pole at the top which would uniquely allow it to remain so. 

 

Now, I don't know why it is important to your project that this part be so perfectly spherical, but if we need to to be truly more so then we can't abandon that top pole completely, but instead should dissolve loops to minimise the complexity of it whilst still preserving it, by merely dissolving every other edge that connects to the pole like so...

 

image.thumb.png.ac471574efbcb64fb7477f6da3685fb8.png

 

Now we preserve the pole, but make it a relatively harmless 6 point one, which as you can see, still works under SDS, and would now be able to slightly more accurately match the underlying topology of the object you are shrink-wrapping around.

 

But unless you have a great reason for that immaculate spherifying, and for keeping that pole I don't see any limitation to doing it the first way I suggested, which is the more perfect SDS result, and the deviation from true spheroid remains minimal to the point where I can't see how it could matter ! 🙂

 

Let me know your thoughts on all that...

 

CBR

 

 

 

 

 

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Hi Cerbera

 

Thank you. Both your options look great. And explaining both routes lets me progress pass this problem by having a full understanding of the facts. But, I am doing something wrong, I can't recreate your option 1. Please see the attached file. 

 

When I shrink-wrap – my shrink-wrap goes inside the sphere and doesn't look spherical like yours. I think I'm missing an essential bit of info regarding the shrink-wrap process. There is something I'm doing in this instance which is wrong. I'd appreciate it if you could point it out to me!

 

I'm really happy with the quadded option as recommended.

 

Thank you

Shoulder_0004_New_0002.c4d

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  • Solution

You're welcome, and glad it helps.

 

I didn't use the shrink wrap at all to get my first result ! I would have just retopo'd that by eye into quads !

But being the slightly hard-core modeller I am, I do of course have the HB Modelling bundle and it was that, and its curvature-aware quadcaps function that let me do that by merely selecting the top 12 tris and doing it in one click. The joy of that (and indeed its points-to-circle script) is that they take the existing curvature into account when quadrifying, so if your original pole defines the top point of the curvature it is able to acknowledge that in its scripting, and so calculates the near perfectly spherical surface for us with no further adjustment required.

 

If we were doing the same procedure manually then I still wouldn't feel the need to do it with shrink-wrap, but in that case some minor adjustment of points would be necessary after the quadrification, but even that should be as simple as moving the top-most points up a bit into a more spherical form...

 

CBR

 

 

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Oh WOW! I have the HB modelling bundle but was not aware of this feature. Through modelling the face I've done, to accompany this arm, I've got pretty good at manually moving the points, and I could have manually replicated the curve. That's how I approached the skull. But, I'm trying to learn a new technique, especially to get solid at the basics where possible and this is an excellent example of that. I've spent ages trying to do this as I thought there was another way. And with your help, I've now learnt at least four valuable lessons, hugely appreciated. Thank you! Also, it's amazingly helpful to know that you would have considered manually moving the points into place. Especially as that's a little technique, I have practised a lot recently (the head).

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