Alpha wrap around cylinder : ring creation

[system]

Hello everyone,

I was wondering if this is possible in ZBrushCore :
Use a texture like these : https://thumb1.shutterstock.com/display_pic_with_logo/347185/350304668/stock-vector-collection-of-celtic-patterns-and-borders-goidelic-designs-vector-illustration-350304668.jpg
And "wrap it around a cylinder as alpha.
The goal is to then use the extract function to create a ring, something like this :
https://ae01.alicdn.com/kf/HTB1JTWcPpXXXXbnaXXXq6xXFXXXg/Fashion-Greek-Key-G-Pattern-Stainless-Steel-font-b-Rings-b-font-for-Women-Couples-font.jpg

Or by simply using the alpha around a cylinder, embossing the details around a ring :

Is this possible with ZBrushCore, or only in ZBrush full (like with the uv mapping) ?

Thanks!

[marcus_civis]

Yes, it is possible but it’s a bit of a fiddle.

Although you can import an OBJ with UVs into ZBrushCore you can’t apply an alpha (or a texture map) directly onto the mesh using the UVs. However, the Surface Noise feature does allow you to apply an alpha using the UVs and then to deform the mesh. In the example image, I used this deformation to help mask the cylinder and then restored the mesh by importing a high res OBJ I’d saved earlier. I could then do the extraction.

The image shows the basic step-by-step. When masking, I used Shrink Mask and Sharpen Mask to get it how I wanted. (And obviously the ring is incomplete - I just grabbed the first knot image I found.)

HTH,

Attachments

[master_wayne]

Wow Marcus, I had been looking into the noise maker for the very same reason and your method finally gave the answer. Thank you very much!! Very helpful.

[system]

Thanks a lot Marcus!
Will try this evening and post a pic hopefully

[marcus_civis]

Great! Yes, do post pics.

[system]

I see how it works!
Have to fiddle with it but I will

What was your initial object, an kind of ring with very thin “walls” or only the walls with no thickness (not sure how to say it…).
When I apply the noise, i’ve noise both on the outside and on the inside of the ring then it’s hard to use the result to make the alpha.

And how does the alpha you use in noisemaker looks like (square, rectangular,…) I’m having some trouble to get it correctly aligned.

Thanks for your help a lot Marcus (beginner with ZBrush here )

[marcus_civis]

The initial object is just the Cylinder3D with the top and bottom cut off. It has no thickness. Turning on Double in Tool>Display Properties will show both sides. The low res OBJ and the alpha are in the zip attachment below. It’s important to subdivide the mesh and then export the high res version so you have a copy.

I did quick UVs but they aren’t the best. So long as your image matches the UVs it will fit perfectly in Noisemaker. Make sure you have the UV option on (as in my picture in the early post) and load the image by clicking the little Alpha On/Off button bottom left of the window. I set the Strength to 0.5 and the Mix Basic Noise to 0.

Once you’ve pressed Apply To Mesh to create the actual geometry it will displace inwards and outwards. But that doesn’t matter. It’s just so that you can mask the cylinder and leave the design. Make sure Perspective is off and you’re looking down on the model. Hold Ctrl and select the MaskPerfectCircle masking brush. This will create a perfect circular mask. Hold Ctrl and start to drag out the circle. Once you’ve started dragging you can let go Ctrl but don’t let up the mouse. You can drag away or towards the center to change the size of the circle and you can hold down the Spacebar to reposition. Once you’ve let go you can improve the mask by pressing ShrinkMask and SharpenMask as necessary.

Now you import the high res OBJ you exported at the beginning. This is essential. What it does is get rid of the displacement and leave the masked cylinder. The OBJ you import must have the same number of polygons as the mesh you are importing into, otherwise you will lose the masking. You can then invert the mask (if you want) before doing the Extract.

[system]

Hi Marcus,

Thanks for all the detailed infos!

Will try again, my final result yesterday wasn’t bad but not exact

How did you get to the alpha (PM3D_Cylinder3D.PSD) ? (how to find the uv on which to apply the pattern ? the gray area in the psd) ?
I tried with a rectangular alpha and it was really hard to get it to wrap in noisemaker with the uv option.
Here is the alpha I used (or maybe I used a square one with more white on top and bottom, can’t remember):

Will try again with your files!

[marcus_civis]

The example I posted doesn’t have the best UVs. The white area in the PSD is the bit that maps to the cyclinder. It was just meant as a quick example.

The best UVs should fit an image neatly to the shape so that there is no distortion or gaps. I’ve attached a new Cylinder OBJ with the original UV texture and the knot pattern you posted applied to it. I used the free UVMapper program to assign the UVs and export the template:

https://www.uvmapper.com/

This little program allows you to “Save a texture map” which you can then load into Photoshop or another image editor and apply the design you want to use. You need to make sure the design fits neatly onto the grid that UV Mapper puts on the texture map it exports. This is so you get the best mapping onto the model. Then apply it in ZBrushCore’s Noise dialog box - not forgetting to turn on the UV option! It should fit without any adjustment. You can see the design better if you change the color in the selector.

HTH,

[system]

Thanks a lot again Marcus!
Hadn’t thought about using an external uv mapper…

I’ll try again and post pics here!

[kassapism]

Dear Markus,

A little help please.I’m about to start with zbrushcore and wondering if you can add/use those alphas

ArtStation - 100 Tileable Displacement/Alpha Patterns Part 2 | Brushes

Is it possible or only in zbrush?

Thanks you
Michail

[marcus_civis]

Hi Michail,

You can import alphas into ZBrushCore for use with the sculpting brushes to create different effects. For tileable alphas you are limited to placing them by hand - there is no automatic placement.

HTH,
Marcus

[kassapism]

Thank you so much Marcus!