question about rendering and export

[cannedmushrooms]

new2.jpg Ok heres my question
When you render in zbrush is there a way to turn up the resolution so when you export the PSD image it will be at a higher resolution than 72.

I want the export to be at least 300 DPI so I can make a poster. how do you set it so it exports at higher resolutions.

[Bas Mazur]

Only in Photoshop you can higher the resolution. In ZBrush you can only make the canvas as high as possible

[lemonnado]

Bas is correct!

All which counts are your actual output pixel.

Warning! Rambling follows:

It's a bit confusing and I hope I don't mess up. If I do, please correct me.

Considerations:

Printer:
Every printer has a 'native' resolution. Like an LCD screen a printer has a fixed 'raster' it can output. That defines the maximum output resolution of the device. It defines how small the smalest dot is it can reproduce. If a printhead can spray a drop as small as a 1000'th of an inch then that is the maximum resolution of it. 1000 DPI native. Typical Laserprinter can squeeze 600 tiny toner dots into one inch. 600 DPI native.

The more dots per inch the more expensive the device is typically.

Horizontal resolution is typicaly defined by the printhead / laseroptics.
Vertical resolution is typicaly defined by the transport mechanism.

Laserprinters are usually 'square'. 600x600 dpi etc. etc.
Color Desktop Inkjet printers usually have a higher horizontal resolution than vertical. (Cheap transport....grrrrr).
Let's assume in any case the resolution is 'square'. Other ratios are irrelevant in this context.

Let's assume pur printer has 1000DPI 'native'. 1000x1000 pixels 100% unfooled around with.

Your picture file has 2000x2000 DOTS.

Without ANY trickery. 1:1 transport of the pixels into the printer. The resulting image in our case, would be 2 by 2 inches 'large'.

Great. We have created a miniature! Considering this setup, a full US Letter page (8x11 inches) would have to have 8000x11000 dots in the picture file.

HUGE! Email that my friend! 32 bit color... ouch...

What now? There are two ways to go 1. Scale the picture in Photoshop or equivalent to 8000x11000; 2. Use the scaling process available in most printers/drives.

That process is the so called RIP (Raster Image Processor). A RIP can be included in a printer driver or even be a separate box if high resolutions and a lot of trickery are necessary to provide output. A RIP can be a simple 'resolution matcher' or as complex as a Postscript language interpreter which has a lot to do in little time.

In case of our desktop printers our pixel data is transfered through the printer driver which in turn matches the original pixels to the desired output resolution. If we tell the driver our picture has 500 DPI and we send it through the driver the driver will re-calculate the data and 'stretch' it to the size of 4 inches. 2000/500 = 4.

So if you set your 2000 dot wide file to 1 dpi you can cover 2000 inches with each dot being 1 inch large. That would look impressive from a distance. A far far distance. Insted of printing a single dot and then advancing an inch to print the next one. The RIP in it's simplest setting will fill the 'gap' with the color of your dot. Thus making your dot's 1x1 inch big.

This can be optimized further. We shall not forget the printers native 1000DPI. The printer still prints 1000 Dots per inch. If the driver is clever, it interpolates the hue.saturation and whatever not shift between the dot's in our file and gradually change the pixels it fills in between our original pixel and the next pixel one inch away.

Printer Drivers usually offer a lot of options regarding all this. It is beneficial to take a closer look at the pronter driver settings while printing 'art' rather than pie charts.

Personally... I prefere to adjust my output in Photoshop towards the native printer specs and then have the driver do as little as possible. The size of those files is horrible but the control I have is better than with the printer driver I have. I leave the tweaking to you. However, I have to work real real hard to be better than my canon driver. Most of the time I simply pump the data throught the driver without thinking about it. Printer driver came a long way!

I hope you have another look at your printer ans the 'secret' and usually neglected inner workings.

Happy hollidays!
LemonNado

[Frenchy Pilou]

Can you make a little schema of your lesson ?
For example with an image of 2048*2048 "pixol" from Zbrush to a possible print book or a poster with different solutions ?
Zbrush --> Toshop --> Printer --> Paper
Thx by advance
Pilou

[cannedmushrooms]

That would be a great lesson.

Heres 2 more questions for the Gurus

1. Export a document with a transparent background. Is it possible?
2. Export a document that has layers in photoshop. Zbrush has layers so is it possible to export the psd with the same layer structure?

[Meats Meier]

I'm no Guru, but here are your answers:

1 - Yes. You can grab the depth from any layer (or merge them all together and get the depth of the entire scene) by doing a Alpha> Grab Depth and then adjusting the curves in PS to get a pure black and white mask that you can use to seperate the elements. Also, maybe even easier is to change your background to a color that doesn't excist in your scene (bright green perhaps) and then select only that color in PS, invert the selection, and there you go. There will be no anti-aliasing on the edges (because you can't anti-alias Zdepth information - Pixols).

2 - You can render each Zbrush layer seperately by hiding the other layers and rendering. Export one at a time. To get the transparency for each, see answer #1. Expert mode - You will find that when you render each pass seperatly, things may not be perfect. For example, layers in Zbrush aren't like PS - they all excist in the same 3d space. You may need to color things on the other layers with the flat color material and the rgb of the background to use basicaly as a mask. You will need to save out several versions of the scene and do this once to each layer.

[Bas Mazur]

PRINTER ............OUTPUT DPI...............INPUT DPI


Monitor...................96...................... .........96

Laserprinter............300....................... .....120

Laserprinter............600....................... .....150

Inkjet-printer...........300............................. 110

Dye-subprinter.........300............................ .125

Imagesetter............1250+...................... ....300

It depends on the printer you want to use how many dpi you need.
An image of 1000 x 1000 pixels at 300 dpi has the size of 8,47 x 8,47 cm.
The same picture (if you want to print it on an inkjetprinter)at 110 dpi has a size of 23 x23 cm
The max size of ZBrush is 4096 x 4096 pixels. This is the same as 34,68 x 34,68 cm at 300 dpi. At 110 dpi the size becomes 94,58 x 94,58 cm.

I hope this can help you!

[Bas Mazur]

Meats
Grab depth, where to find this?
Mostly I use another way to do it. All the materials I used I change in a basic material with a high ambient and I use a black fog. Render it without shadows.

[aminuts]

A thing to think about...


if you are using creating and using your textures from Photoshop....then open zbrush and photoshop at the same time. Save the texture you are working on as a psd in photoshop.....then open it in zbrush. this way you can work on layers in photoshop...save it there and see how it combines to one instantly in zbrush.

It's a powerful feature if you have the memory for it. It's great for tweaking layers and channels in PS for detailing and texturing and see how they apply in almost real time in Zbrush. It would be great if I could see the changes at the same time in z as i work in ps...but so far saving first the file is the only way to see changes.....but still a way cool way to work the best of both worlds.

hope that helps some.

[aminuts]

hahaha nevermind my previous post...probably wouldn't help you here.

although maybe for some other project.

it definitely won't work if you are using MM's and guv or auv tiles.

sorry ....I am a bit thick sometimes hahahaah.dohhhhh.

[aminuts]

Bas, I haven't seen the master Meats' dvd's but imagine he uses the grab doc feature of Alphas....see alpha menu.....for a quick depth grab of whatever layer he has visible.

you could then use curves to alter the alpha or use the load curves feature to load curves for highest and lowest alpha curve depths and save those images out to use in photoshop as alpha layers or masks or whatever. world of possibilities there.

you could also use the MRGBZGrabber tool I reckon but the nice thing about grab doc....is it grabs just the depth layer and not both an alpha and texture.

hope that is both correct and helpful!!

[Bas Mazur]

Aminuts,Grab doc grabs depth. Thx!

[andreseloy]

http://www.zbrushcentral.com/zbc/showthread.php?t=3934
Andreseloy

[bicc39]

May one ask who will be doing the printing and on
what?
You mention Poster size which most home printers
can't do.
Will a commericial printer be handling the job?
It raises questions and solutions, if that is the case.

[cannedmushrooms]

Actually its a 36in wide by limitless long inkjet plotter that prints out on either paper or in my case canvas ;) Its a nifty little toy. Keeping the resolution super high is the trick to it all.