Map test

Started by yossam, March 31, 2015, 03:09:25 pm

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Do you see a difference between the rocks? They are the same object, just different maps in the displacement slot. One uses a bump map...........the other a displacement map (which I have never run across before). The maps are different just by looking at them. And no, it's not a normal map. I got one of them too.


The one on the right is displacement map, I guess. I think the one on the right looks slightly better. Am I correct the one is displacement map?
It has been eaten.


Since "real" displacement casts a corresponding shadow beyond an object and bump doesn't cast shadows beyond an object, it seems the more simple ground shadow on the left would indicate the bump mapped one.


The one on the right is bump mapped, the left is displacement mapped. I'm still trying to figure this out. I got a few more to play with. Will post the results.  ::)


The viewer-relative orientation of the two objects is different enough that it is difficult to judge which one is which. If there is a lot of geometry in the base object then there isn't going to be much difference when bumps/displacements are small relative to the geometry. I think I can see some displacement near the top right of the left object that is not there in the right object but rotation might account for it.


Put both objects at origin so the view would not affect the outcome. Same as before............which is which?


Not sure but i think other then kinda different looking image map and because of this,getting a different bump mapping effect there isn't much difference.
You are using a different image for bump mapping basically. Only if you don't use ray tracing for objects you will get real displacement.
So the question which one is different is kinda mood.


Are you talking about the difference between applying 2 *different maps* (from an external source) in the *same way* in Terragen? I.E. image 1 - bump.jpg - and image 2 - displacement.jpg - and applying them both with e.g. a Default Shader? OR are you referring to applying the same source image, but for one render using Raytrace Objects (only renders bumps, no displacement), and the other with Raytrace Objects off (displacement will work)? I assume you mean the first thing, in which case I would wonder what the difference between these maps actually is, where they came from and what they're intended for. I would normally guess that a Displacement Map intended for another app would be lower resolution than a Bump Map simply because Bump Maps can portray finer scale detail better than large scale detail, and at a lower render time cost than fine scale displacement. I don't think for Terragen use that it is particularly useful to have both, I would just favor the one with the greater detail. A *normal map* and *vector* displacement map are both different things and would have to be handled totally differently.

- Oshyan


April 01, 2015, 07:58:15 am #8 Last Edit: April 01, 2015, 08:01:18 am by PabloMack
Quote from: yossam on March 31, 2015, 04:44:47 pmPut both objects at origin so the view would not affect the outcome. Same as before............which is which?

I can see some displacement outward along normal in Maptest2a relative to Maptest2. It's not a lot but noticeable.

Was it the same (UV) map that was used in two different ways?


April 01, 2015, 02:23:48 pm #9 Last Edit: April 01, 2015, 02:28:47 pm by yossam
They are two different maps, one labeled "bump", the other labeled "displace". I tried to post but keep getting error message about being too big. They are 4k maps but the file size is not showing over the limit. I'll keep trying.


One in each post maybe. Or reduce into jpg.


Had to do a screen grab............they would not post regardless of what I saved them as. Strange........... :o


April 03, 2015, 02:04:45 am #12 Last Edit: April 03, 2015, 11:12:34 pm by Upon Infinity
I came across a similar conundrum while I was doing all the modelling I've been doing lately.  I actually at first panicked, thinking I was using the wrong maps.  I came to the conclusion that different maps simply have different uses for different programs.  A displacement map first and foremost is for, well, displacement.  I believe bump maps were for before many programs could do actual displacement or for just a different effect.  Personally, I prefer the bump map as it gives finer detail (and it can also do displacement)  There is a difference, to be sure, though it is subtle..  I put a small video together of me flipping between the two images.  I think for your experiment, though, that you should have dropped the colour map so the effect could be seen easier.

It could also be that some renderers support not only displacement maps, but also bump maps, as well, giving you not only the displacement (which is rougher) but also the fine (fake) detail of the bump map.


Without the diffuse................

j meyer

You still didn't tell us if you rendered with ray trace objects on or off.
My guess would be ray trace on.
The other thing is you don't show the object without displ or bump map.
Makes the guessing not easier.
The look of the last pics seems to indicate that your model might have no
normals,thus the facetted appearance.(normal smoothing doesn't work without
Judging from the pics of the maps the displacement is meant to do the big
shapes that would alter the look of the undisplaced object.This does only
work with ray trace off in TG as others mentioned already.
The bump map is for the fine detail that wouldn't cause visible changes in the
outer shape of the object.
Depending on the program you could use the normal map for the latter as well.
Bump or normal mapping as a last layer on a displaced low or mid poly model
that's a pretty common approach.Works for many apps and game engines etc.