[bruno.sdi]

Hi there,
I'm having trouble on getting displacement to work on some geo from zbrush. The scene is preety basic as you can see...
On the placemat I sculpted all the details needed on it's border and exported the low res geometry and baked a 32bit displacement map on zbrush (4k). I used the uvmaster on zb to unwrap the object.



This is the result I'm getting out of that displacement map...


Bellow is the material settings. On the base I just set a quick colour and an extra BSDF for rough reflections as at this stage I want to test the displacement map. Acording to the manual if a map was generated on zbrush, the Subdivision Method should be set to Catmull/Loop.


I need to have a massive output for this render (around 20000x6000) and those tests were rendered at 9000x2700.
Any idea the best way to get all the detail out of zbrush into max (in my case) and maxwell? It's a very fine detail I i thought using displacement would be the best but with all the problems I'm having, I think maybe is easier to bake a normal map and see what I can get out of it...

Thanks.
Cheers!

[Mihai]

Have you tried with a higher subdiv?

Although for such fine detail, why not just use the geo directly? With pretesselated you don't save anything on RAM anyway. You might as well avoid a complication and just use the high rez mesh.

Btw, what are you going to use this on, how is it going to be printed, that it needs 20 000 pixels?

[bruno.sdi]

Hi there Mihai,
Thanks for your reply. The original geometry from zbrush has around 7.5ml polys... It's a bit crazy to bring it to max, but as I'm running out of possibilities, I'll give it a try.

This image is actually made to fit different campaign formats, mainly outdoors, so the plan is to render the biggest format and that way have all the other. Those 20000 are actually for 2 or 3 outdoors together that forms the whole image...

Thanks for your thoughts.

Cheers!

[Mihai]

This is again one of those crazy clients requesting this.....at what rez will these be printed? Because probably it won't be 300dpi......or even half that. Well, for big posters they will probably use offset printing? Then you get into lpi (lines per inch), which at a viewing distance that big posters are generally viewed at, they will probably be printed at around 85lpi or less, which means at most you don't need more than 120 ppi (pixels per inch setting in Photoshop). If they will print it at 50lpi, then you can easily use 75ppi. 20 000 pixels at 75ppi is almost 7 meters wide if offset printed at 50lpi. Newspapers which are held at arms length are usually offset printed using 85lpi, so you can imagine a billboard viewed from 5 meters away doesn't need that much.

I've said too much....

[Fernando Tella]

Try to make a mxs reference of the geometry so the scene is easier to handle.

[Tora_2097]

http://www.maxwellrender.com/forum/view ... 35&t=42811



May I quote myself on the topic of render resolution:

I found that the 2 major factors are the required viewing distance and -most of all- the level of stupidity on the clients side.

You see now Dario, you should update the docs again.

I too would try this with the raw mesh. Maybe you can decimate it further or delete backfaces? Since this renders probably quickly you could try render in 10k and upscale in post especially since your displacement map is only in 4K anyway...

Ben

[seghier]

Try to make a mxs reference of the geometry so the scene is easier to handle.

yes , without use displacement

[bruno.sdi]

Mihai, I totally agree with what you say, and most of the times I can get them to understand size/printing, viewing distances etc... Although this time maybe there is probably a point on it, they have to print the image as wide as 12m

Already have the mesh out of zbrush into max, will try to delete as many polygons as possible (making as a reference is a good idea Fernando, the scene is indeed very slow at the moment. Won't be able to render the full res geometry without the displacement map until Monday, but I'll post the result then along with the normal map version.

Thanks to you all,
Cheers.

[rusteberg]

Well your disp uv tile may be 4k, but the way you've packed that uv your getting maybe one or two hundred pixels of resolution from that displacement map which is then being stretched well beyond its limit at the size/proximity of your rendering making it pretty worthless as a bitmap in any material slot.

Ideally you want to have that unwrapped strip of ploys cut unto X number of segments (chunks/islands) so that your uv tile maximizes pixel consumption at render time. For instance cut that strip into six parts and stack them on top of each other in your uv space. And at that proximity and size you're going to need your ploys to consume as much uv space as possible and at least double your 4096 uv space.....

edit: after looking at it on a compooter monitor it seems you should be picking up some displacement detail from the map you are using. what happens if you convert that 32 bit map from zbrush to an 8bit .jpg and increase your displacement subdivision from 2 to 4?........

edit x2: and 0,2cm seems quite low for a displacement value...... seems at that value you could get away with using bump or normal like you suggested... but you're going to have to increase the crap out of the size of your uv tile export in order to get the detail you have shown in your original sculpt based on the way you unwrapped that sum'bitch....

[bruno.sdi]

Rusteberg,
Thanks for tips... I know the uv packing is not the best to maximise the displacement map, I did a quick test breaking it into islands but then zbrush surface noise wasn't working so well, you could see the seems on the pattern. To be honest is probably my fault, I should fix those islands in order to have clean seems but don't have much time for it.
So I tried to export the high res geo and it seams to work ok, I think that will be the final solution (not ideal I guess)...
Here is a test (the light setting was changed by the client).