ZBrushCentral

How To ZBrush over Human Photograph?

ZBrush Usage Questions
#1

Hi,

New ZBrush user here, and I’m excited about the possibilities.

I need to put some gnarly, viney looking veins and raised bumpy rashes onto still photo of a dramatically lit person. Any workflow advice?

Should I attempt to match model the person and vein him up and put out pure CG synthetic texture and lighting that approximates the person either from Zbrush or Maya for compositing in Photoshop?

Or can I somehow read the photo into Zbrush and used it as a base texture there and “push the image around” somehow?

#2

There are several ways of doing this but probably the simplest is to load in your photo on a plane. You might like to check out my Image Plane plugin which simplifies the process. (It makes keeping the original image proportions easy.)

Once the image is on the plane you can go into Edit mode and sculpt it directly if you wish but be sure to turn RGB OFF or you will destroy your image. In this image I bulked up the general shape of the fish. To add detail in Projection Master you would have to convert the plane to a polymesh first.

When you’re happy with the basic shape you can add 2.5D details. For the veins here I just select the appropriate alpha and the drag rectangle stroke.

Then adjust the lighting and shadows and you’re done!

trout.jpg

#3

Thank you very much

#4

have to admit I’m having a little trouble applying this to my application.

I have a dramatically lit person in a foresortened pose - I can’t really treat it like it’s a vertical wall.

#5

If you can’t use this method then you may have to build a matching 3D model first but that would obviously be much more time consuming, added to which it could make controlling the lighting more difficult. It would help if you were to post an image.

#6

There’s a variation on this theme, that might be appropriate, here: http://www.zbrushcentral.com/zbc/showthread.php?t=30188

#7

Unfortunately I can’t post an example of the specific case, but I think I have a quasi solution:

Work flat on a wall (as I believe the fish example above is?)

Light it from multiple, carefully chosen directions to simulate changes in planes on the vein substrate,

Combine the different renders in Photoshop

#8

I’m stumped once again - this time it’s on how to integrate a photo with simple brush.

I want the photo UNLIT - it is already a photo of a lit object and should not participate in the ZBrush lighting.

I want to draw on lit, uintextured simple brush “toothpase” on top of the photo.

I want to somehow see the photo where the brush stroke is not yet applied.

I want to spiral hook some hooks out of the toothpaste and have them stand in front of the photo without themselves “involving” the photo in the distortion.

Can this be done with layers somehow? I can seem to get it to work.

#9

Use the flat material. It doesn’t interact with lights, so the colors in your photo remain constant.

#10

Yes, but I want lighting on the simple brush strokes and spiral hooks.

So -

Plane3D with a texture map and flat white material? And then brush over it with another material that contains color but no texture? And do a zadd with that? I guess?

I’ll try along those lines.

#11

I think the fish example you did above will be very helpful to me - it’s taking me a bit to wrap my mind around some of the details - I’m going from 0 to full speed in just a couple of days.

#12

OK, given the restriction imposed by the lighting of your photo you may find this method the best to follow. It also happens to be the simplest so there’s a benefit. :wink:

Rather than go through the details here I’ve recorded a quick zscript tutorial. Unzip the file to anywhere on your hard drive then load the Photo-Sculpt.zsc file from the ZScript:Load button. Press the Play button that will appear towards the bottom left of your UI. To slow down the playback you can set the ReplayDelay slider to 200 or so. Check that ZScript:ShowActions is pressed to clearly see the proceedure.

Franky.jpg
[with apologies and acknowledgements to Mr Karloff]

HTH,

#13

This method makes better use of ZBrush’s lighting and modeling capabilities. Some overlay work would be necessary in Photoshop to restore the exact lighting of the original photo but you’ll see the result is more dynamic. I’ve not commented the zscript in this case so to briefly summarise:

  1. The image is imported onto a plane of the correct proportions. The plane is converted to a polymesh.

  2. The texture is used to mask the plane to provide a guide for quickly bulking up a rough shape. Use the Tool:Masking:Int button to apply a mask from texture intensity. Remove the mask by holding down Ctrl+Alt while painting on the plane in Edit mode.

  3. The plane is dropped in Projection Master and some veins added.

  4. A bit of smoothing of the mesh to tidy the details.

  5. A new blank texture is created (2048 x 2048) and AUVTiles UV mapping applied to the plane.

  6. The plane is dropped in Projection Master and then the photo put in place using a new plane. When picked up the photo has been applied to the new plane texture. Doing it this way ensures that the photo is not distorted by the plane deformations.

  7. Lighting is adjusted.

Note: if you have ShowActions switched on for playback of this zscript you’ll see a lot of the extra stuff associated with Projection Master. There’s no need to follow this.

Franky02.jpg

#14

These are very cool and educational and useful - thank you for them. I need to analyze it a bit to better understand it but I have a pretty good sense of it now.

I get an odd leading “splat” when I touch pen to wacom - and in the case of the sanke hooks I get a leading square base.

#15

the case of the first Frankenstein example, the Z displacement was key to me gettingthe “nonexistent paint” that was elluding me before.

Is the Z displacement a relative nudge in that direction, or an absolute depth?

#16

Great, I hope you find the stuff useful.

The Snake Hook ‘square’ is a result of using the brush on a different material - mostly it is caused by filling the canvas with Flat color and then using the Snake Hook with a different material. The solution is to create a second layer (if necessary a duplicate of the first) and push it back behind the first by putting +1 in the Layer: DisplaceZ slider (note negative values bring it forward). As long as the current layer is the ‘behind’ one then the square is hidden and ceases to be an issue.

On the tablet problem, you might want to check out this Wacom issues thread.

#17

Yes, you need to make sure the layer is only just behind the other, and make sure the ZIntensity and build up is adequate for the marks to show.

Is the Z displacement a relative nudge in that direction, or an absolute depth?

It’s an absolute depth, where one unit equates to a pixel width of depth. In general 3D objects and ‘fills’ are placed at Zdepth 0; the clipping plane will be at a set depth behind this, depending on the size of the canvas. I’m not aware of the exact relationship but for a canvas of 640 x 480 it will be at Zdepth 1280, for 1280 x 960, 2560. You can move a layer backwards [positive Zdepth] until it disappears behind the clipping plane (and beyond but you can’t see it!) and forwards [negative Z]. Movement in either direction can be up to 4096 Z units at a time, up to a maximum of 16 times whereupon the layer is back where it started; there’s therefore 65538 Z units in total, 32768 either side of the default 0 position.

I hope that’s interesting. :wink:

#18

With your Wacom you might try this:

Open the “Wacom Tablet Properties” panel.
Double click on the tablet icon in the top row.
Select “Recognition Data” and click OK.

This may help.

#19

Yes, the Wacom driver “recognition data” is a winner -

it solves the problem nicely; thank you.