Hi,
I have a detail photo from a church. I cut it out, made it greyscale but it makes a very flat and rough surfaced alpla mask in Zbrush. What am I doing wrong to be able to get the most out of the photo to make into a 3D model in Zbrush.
See photo
An alpha or heightmap from a single photo in general will not produce a good result. Photoscan (or similar photogrammetry solution) would be one way to produce a 3D model or heightmap from many photos.
The simple reality is that a photo contains no depth information. It is simply light and shadow. We know from our own experience looking at such objects just how it would be constructed in 3D. For example, with a photo of a face, we know that the nose is going to be the closest point to us. The computer lacks this real-life knowledge.
What this means is that there is no substitute for human sculpting. You can apply your image to a grid in ZBrush and even project it onto an object but you will have to sculpt it yourself to interpret the light and shadow into actual depth. Once you have that, ZBrush can then use your sculpt as the source from which to create a depth map – which will be your alpha.
Hi - I made a B/W alpha in photoshop. Had to neaten it up with the black brush.
When I added it to Zbrush and made a mask alpha I got some weird marks on the black area (at the rear in the image) that seem to corresond to my brush marks. Now I made sure the image was 8bit grayscale and max contrast, so how is it possible that Zbrush sees this and does not give me a flat bottom to my mask.
Hope someone can advise me. How could i be possible that Zbrush could see black on black marks?
Regards,
Simon
It only appears to the same black on your monitor. If you use the Info palette in Photoshop you can see the greyscale value change as you move the cursor.
The black you painted with did not match the same greyscale value as the black in the image.
Hey zymon
“…that seem to correspond to my brush marks.”
three possible problems that I can think of in Photoshop:
you used the Hue Cube in the Colour Pallet to select your black. This often only gives a 99% black. It’s best use the swatches for 100% black or white, or to use the Pic Forground Colour popup where you can check the numbers.
you used an adjustment layer (levels or brightness contrast) on the image, then picked your black colour from the image but the picker was set to ‘current layer’ and so ignored your adjustment layer.
your round brush was not set to: 100% opacity, 100% flow, 100% hard edges, transfer off, wet edges off
Hope that helps 