confused on mapping

[nomeradona_cg]

im attaching this image of the hotel room interior. there is no problem in adding bump on the floor for me. my problem is how to apply the material on the cupboards, they appy on top and front but they dont apply on side. the second cabinet on the left bedroom is different again. the big board at the back of the bed has no map ( its the original sketchup texture. im still confused with Mapping types (objext xyz, planar and explicit map channels, i dont really know the difference and how they really work) in su its really easy to apply texture or even the linked materials. but its not really realistic enough because of lackking bump map. its easy to work by applying diffuse and bump map together, but i have difficulty in mapping them to the object. can you please shed more light on this.

[dcauldwell_cg]

Re: confused on mapping

I am also confused by the mapping - of bumps.
Whenever I try to add a bump map to a texture, the scale seems completely wrong - usually too fine. As a newbie (!) I am probably doing something completely wrong, so a basic tutorial would be welcome. (I've read Micha's 'making materials' but I'm still none the wiser.

[joe_b]

Re: confused on mapping

The 3 types of UVW mapping that we have right now are as follows
[*]Explicit UVW Channel - this means that you are relying on a specific uvw channel that the geometry has. In Sketchup there is, at most, 1 channel provided. The mapping is a bit of a headache in Sketchup. In most other 3d modeling applications surface uv coordinates are always generated. In Sketchup they are only generated if a Sketchup texture is applied to the face or group. So if you are relying on an explicit channel - but do not have a Sketchup texture applied to that geometry, you will get random, incorrect, results.[*]Planar World Mapping - this is a V-Ray uvw generator. It means that it will apply a planar mapping to the geometry it is applied to, in world-space. Meaning the top-left of the face will be 0,0 - and the bottom-right will be 1,1 in uv space. [*]Object XYZ Mapping - this is similar to the planar world mapping but is in object-space instead of world-space.


So I do completely agree that the mapping is a bit of a mess right now. I suppose what we need to do is make another uvw generator for surface uvs, or somehow ensure that the Sketchup geometry always creates surface uvs. Then you can just use the explicit channel stuff and not really need to worry about the mapping so much.

[nomeradona_cg]

Re: confused on mapping

applying maps in sketchup- i really find it really handy. because you can see the way you will apply the map on the surface. then when you move your model and use it in another computer, you can still see the map there.

the way vray does mapping is i think closer to max and vis. so with this i think they are more complicated IMHO. and i just found out too that if you save your file to a handy drive and openned it in another computer, all the bitmaps are gone. the bitmaps will not be applied because vray will find the root file where you put the bitmap that you use.. the same as max and vis right?)so if you want to open your file to another computer be sure you will also copy seperately the bitmaps.

based on above context i found su as more efficient.

since this is an evaluation software and this is for sketchup, is it possible that vray su will apply the map the way su does. and the way you scale and see the map on the object.

if this is complicated, is it possible then to see the size of your map (like a tracing paper) over the plane or faces where you want to apply the image. rather than entering numbers, then render to see if it works. (this part is really taking a lot of time).

oh another thing, those pushpins of sketchup are again another very useful tools in mapping textures. if vray su will behave like this. wow, what an enhancement.

[dalomar_cg]

Re: confused on mapping

Here is a pretty good resource on how to use the sketchup mapping tools that I found a little while ago. I believe in order to use the mappings that it generates, you will have to first apply the texture via a standard su material and then use a vray material wrapper for anything else you want to do with it.

Here's the link:
http://download.sketchup.com/OnlineD...ionTexture.htm

[joe_b]

Re: confused on mapping

The only way for us to use the Sketchup mapping, I believe, is if we do everything via the basic Sketchup material. Which is fine for simple materials that do not have multiple layers with multiple different maps on them.

We'll have to figure out a way to utilize Sketchup's mapping - but right now the only way to do it is to apply a Sketchup texture to a face and use explicit map channel 1 to reference those uvs.

[nomeradona_cg]

Re: confused on mapping

i don't have any issue on mapping using sketch up. it's all there.
wrapping materials is of course the way to do it. the question now is when you apply bump material on top of it (particularly wood, brics or course fabric.) i have the difficulty in figuring out the bump map over this material. let say i want to make my wood grains deeper and the concrete grouts. i would not have the full control on the bump map. so you will do a lot of trial and error process here (also keep in mind, that you will use test render here) Assuming you have 10 trials and each trial say 10 minutes long, how many minutes you will spend on this?) if you will for example see the bump map how it will apply over the sketchup material,(the way Su does- Dalomar attached on this thread) then what an innovation. this is what im saying here.

remember sketchup is a very efficient program that is why i love it. so if this engine will handle mapping the way su does. what an engine.

by the way,the speed of vray woooooooooooowwwww, im so surprise. if you will learn your way, it will be pleasure.

[joe_b]

Re: confused on mapping

Yes- I believe the only way to do your fabric issue would be to use multiple mapping channels - which sketchup doesn't provide out-of-the-box. We'll just have to find a solution

[nomeradona_cg]

Re: confused on mapping

im doing a lot of experiments on applying bump map. since su has only one channel, i ve applied my map seperately. instead of picking all the plane at once. or selecting all the same material. its tedious but it works. (linked material applied with bump will be difficult as the diffuse bitmap and bump map does not match.

by using photoshop, you have to create your bump map by desaturating the diffuse map you will use and apply a high contrast. this bump map then will be use hand in hand with the diffuse map. scaling of both diffuse and bump maps should be the same to have an accurate matching between them. as a rule of thumb better to start at .01 scale.


cheers

nomer

[dcauldwell_cg]

Re: confused on mapping

nomer

I am also trying to get this to work, and would be interested in your settings.
I have created a new material, based on 'matte plastic' and tried to apply a bump map I made from a gaussian texture.
I find it renders ok in the preview when I select 'map channel 1', but keeps reverting back to 'map channel 2'. Therefore when I render the scene, there is no bump. >

I am using the default 'gi_irmap_medium.visopt' to render it.

Its driving me potty! I will have to leave it for now as it is taking up soooo much time.

Let me know how you get on.

David

[nomeradona_cg]

Re: confused on mapping

dcauldwell,

forget about that channel, it will always go back to no.2. The technique is to select one face first then apply the texture. next select again another face, then apply the texture and so on and so forth. as for the u and v scale i always start at .01

[dcauldwell_cg]

Re: confused on mapping


nomer

At last. I'm getting it to work. This test on what sketchup calls a sphere (ie a polygon) I applied 'shiny chrome' to the sphere generally, but with a few 'painted' sections, both with a gaissian bump map applied. Initially I could clearly see the effect on the chrome, but because of the scale and colour of the painted section you could not see the bumps. I changed the scale of the bump, (to 0.1) and zoomed in, and there it is! I guess the scale of the bump is related to its original image size - mine is 1500x1300. So I can now play around with the scale etc and try it on 'real' scenes. I wanted to add a bump to a leather and chrome Bauhaus chair so I'll now give that a try.

[nomeradona_cg]

Re: confused on mapping

happy for you man.

[dcauldwell_cg]

Re: confused on mapping

Having finally got some bumps, I've got it to work on my leather chair.


This may not be the best texture I've seen, and I think maybe it is a bit overdone, but its there! The u and v were set to 0.004 to get this (the bump map is 800x600)

[nomeradona_cg]

Re: confused on mapping

yeah! finally another su_vray guru is here. very convincing. except those facted curves. how about your diffuse map? .004 for u and v with 600 X 800 good guide.

the soft shadow is very real. did you use the same visopt you shared to me?

congratulation david.

nomeradona