exterior impossible without Vray and Wavgen

[AVATAREA]

OK well that was a sad. Snags with VRay Displacement.

1/ Not possible to stack layers of displacemnt, requires very complex development of a single image wioth all details.

2/ Nothing to place trees upon i.e., no surface shape upon which over 100,000 trees can sit upon. Maybe I could fake it by using a proxy but thats not as easy as it sounds

3/ Nothing to place buildings upon or tee boxes or for carts to drive over.



thought I was going to be really impressed

[Da_elf]

why not just have all your displacement as 1 map. sounds like it would be way simpler and take way less ram rather than loading 8 large sized displacement maps you can load just 1. for placement you can have a stand-in mesh which you can use for placement of buildings etc then get rid of when its time to render

[AVATAREA]

Ok so here's a test.

these 2 images are the exact same file one rendered on basic and one on Advanced Demo

Top one is basic and took 13 mins 24 seconds and the lower one is Advanced Demo and too 10mins 24 seconds.

I see very litle difference between the 2 does anyone else ?






but the time saving is welcome.

[percydaman]

ya Im not sure why they should look different. The difference between the basic and advanced versions are the added flexibility the advanced has.

I also think your giving up too easily on the vray displacement. Learn to use it to its advantage and itll rock. I agree not being able to add displacement on top of each other sucks, but its the reality. Having vray subdivide the mesh and then do it on top of itself, and so on, wouldn't be prudent.

[AVATAREA]

I didnt expect there to be much if any difference , there is in fact a slight increase in sharpness but you gotta lay one over the other to see it.
My point was the benefit of the 30% or so time saving.

The problem is quite simple Percy, the fact is there are only 256 levels of grey and therefore if one, as I am here, is displacing slightly under 400 feet, one foot becomes sub-pixel level.

Therefore to create a layered displacement map containing all the detail means that there is only 1/256th of the 400 feet available thats about 1'9" or so per level of grey. Creek beds and greens require less than 6" and so if I displace in layers and use a black and white image, I can displace by as little as 3 inches and see the result.

I am looking at the possibilty of using HDRI but the snag there is understanding the granularity of the levels within the image.

I havnt given up just regrouping

But thanks for your input.

[percydaman]

for large terrain, I still use a modelled terrain that represents the major changes in height and such, then use the displacement for the finer details.

[CCS]

I'm with Percy. Still intrigued by this wavgen thing though.

[AVATAREA]

Despite my explaining all to you,, you continue to say I should go with VRay displace ???: sheesh. I am glad I employ me and others LOL.

It just wont work with my current business constraints, no matter how many times you tell me its awesome it just wont do,,, what "I" need it to do,, believe me, I wish it would.

Maybe when I can spare a month to look into understanding the accuracy that must exist somewhere in the HDRI solution , there will indeed finally, be a solution that works in this particular scenario,,, Simple really, 400 , 500, 600 or any feet above 128 will not allow accuracy in 256 grey levels beyond 1 foot at a height mean of 256 feet or 6 inches at 128 feet. Most of my work involves at least 400 feet.

Hence multiple displacement from black displacement maps after the first grey scales to fix the overall height.

Does that explain it ?

best regards and thak you all for your input

[mike.edel]

The problem is quite simple Percy, the fact is there are only 256 levels of grey and therefore if one, as I am here, is displacing slightly under 400 feet, one foot becomes sub-pixel level.

Therefore to create a layered displacement map containing all the detail means that there is only 1/256th of the 400 feet available thats about 1'9" or so per level of grey. Creek beds and greens require less than 6" and so if I displace in layers and use a black and white image, I can displace by as little as 3 inches and see the result.

I am looking at the possibilty of using HDRI but the snag there is understanding the granularity of the levels within the image.

have you tried 16bit/channel images for the displacement map?
worked fine for me so far (i have no clue if ecw/wavegen support those tho')
i usually use medium grey as zero height change
white is higher
black is lower

you could also try to use a lower-poly proxy version of the terrain for tree placement, the max displace mesh modifier comes to my mind...

also, wouldnt it be easier/faster to do each sand-pit on its own with a seperate map (as i understand it you currently use a huge map with all pits and waste the pixels between them)

btw, seems wavegen (is it terrashader?) works well with vray, have you stumbled upon any problems so far? i was looking into their eval version which sadly lets you use only one image after alex alvarez (gnomon) mentioned in a workshop i attended last year.

he had some very nifty tricks for doing terrain renderings, including generating height maps from the free usgs DEM data and compositing it with other height images

mike

[tricky]

Oh I seeeeeeee. You aren't actually using Vray displacement, but Max's inbuilt displacement instead.

[mike.edel]

I'm with Percy. Still intrigued by this wavgen thing though.

http://www.wavgen.com/

was evaluating it some time ago - really cool
uses a special wavelet compression format to compress huge maps into workable files
the shader for max can then just load the portions of the map that you are seeing/rendering at the current level of detail (their eval used an satelite image of a huge car lot with about 1m res where you can zoom in to actually see single cars)

you can map that image (i think it was 16k by 16k) to a plane and render it at any camera distance - only the currently visible detail will be loaded into memory

it has one major drawback tho': $850

mike

[jujubee]

Wow. Wavgen looks pretty cool. I kinda wish I had a project that big so I'd have a reason to try it out...

Built-in Displacement? What is that??? ...not to knock it but I couldn't even tell you the last time I used that feature...

[percydaman]

you shouldn't knock it. Like I said, use a fairly low poly mesh and max displacement to get the general terrain features and then use vrays displacement for the finer. Works great.

[AVATAREA]

I would be VERY interested to hear more about 16 bit displacement.
Does VRay Displacement support 16 bit images.

Can you talk on MSN or whatever ?

[AVATAREA]

and re wavgen,, there are several levels at which you can purchase,, including a clever 80 bucks or something a month which eventually gives you a non time limited version.

Oh and it supports JP2 which is imprtant because the free compressor they provide for their propietory ECW format has a 500 meg ceiling on the original array.

So the cheapest version will do you just fine