linked material and bump map issues

[valynkenlyl]

I am using latest release of vray (licensed) with Sketchup Pro

I am having difficulty with the vray and sketchup material editors when attempting to create layered materials.

I add a tile texture with a 1'x1' scale in the sketchup material editor to a box.

Looks right in sketchup viewport and renders in vray correctly.

I then add a vray linked material and select the newly created tile material to link to.

Looks right in sketchup viewport (obviously) but when render in vray the scale is all wrong. My tile texture is now many many times smaller then it should be.

I do not know what would be causing this scale problem from just linking a vray wrapper to the sketchup material. Since the diffuse is read only in vray linked material editor no changes will fix the messed up texture that I attempt from within the vray material editor.

When I attempt to adjust the scale from within the sketchup material editor, the object dissappears in the render.

Not sure if this is a bug or just something that I am doing wrong. Any helpw would be appreciated!

[dcauldwell_cg]

Re: linked material and bump map issues

valynkenlyl

I have only just sorted this out myself, so forgive me if this explanation is too detailed.

1 start with the texture - for example a brick texture (e.g. 'Brick_Antique.jpg' from sketchup)
2 if you don't have a bump map you can make one by making a copy of the above file in photoshop etc. make it greyscale and if necessary add some more texture to it using Photoshop - make it a negative image
3 Save the bump map as say 'Brick_Antique2.jpg'
4 Now apply the texture (in sketchup) to the model - see example (you can also rotate the texture etc in sketchup)

5 Create a linked material in vray
6 edit the linked material and check the bump map box in the material editor, select the 'Brick_Antique2.jpg' as the bitmap (see screenshot) (also read 8 below)
7 render the model (have default lights or a point light on)

You will see that if the face is in the direct light, then the bumps show up quite strongly, and where they are in the shade then they are much less prominent (even indiscernible)

8 If you want more or less 'bump' then adjust the multiplier box of the bump texture editor

Scaling - I am used to getting brickwork to the correct scale, and I scale the material in sketchup. So for instance if my bitmap shows say 20 brick courses and I know that they should be 75mm per course then the bitmap needs to be 1500mm high - set this in the sketchup material editor box. Leave the 'scale' (i.e. the 'u' and 'v' in the material editor) in vray at 1. It should work out ok - see example.


Hope this helps

David

image 1 screenshot of material vray linked material editor
image 2 brickwork example - no bumps
image 3 brickwork example - with bumps

[66popa87]

Re: linked material and bump map issues

dcauldwell,
i want to say thanks for this tutorial. i have mainly focused on the lighting aspect in vray4su. Materials were the next step for me and bumps maps had me a little scared.

thanks to you, i now have a very good starting point for making materials. ;D

paul

[valynkenlyl]

Re: linked material and bump map issues

dcauldwell

Thanks for your detailed explanation. My problem at this point exists in step 2. The assignment of the VrayLinked Material. That is the step...even before I get to the bump mapping.....that is giving me fits.

As soon as I click on the brick material from the select which material to link to window and render, even the diffuse map is rescaled to a tiny porportion, so I cannot even get the diffuse to render correctly again after linking to vray.

I will find the posts that explain how to post pictures and will post images of my problem later (have a meeting now).

I really appreciate your detailed reply. Thanks so much!

[nomeradona_cg]

Re: linked material and bump map issues

valenkyl,

this is always a common issue for sny new user of this sotware. it would reallty be good if we have help file on this area. me here i consider it as exploration and testing. there is always the joy in discovering something. so i should say. these pointers plus some experimentation on your part will help you. (but of course it will be frustrating to the new users who does not have time to experiments).

anyway these are my pointers.

linked material will be the best way, because you could always see in sketchup how the map will be applied. i'm actually wondering how david match his linked material with the bump map (looking on this by this time) but the thing you might consider is completely doing a VRAY MATERIAL instead of linked material.

this is how you can do it.

step 1. prepare two types of map.
1. diffuse map
2. the black and white of the diffuse map. this is easy in photoshop as cauldwell said.( you can saturate it and increase the contrast between black and white)

step 2. open MAterial editor.

2a. make a new Vray Material (rename this material)
2b. open the diffuse layer. on the right color click (m)
2c. texture editor will appear. under type choose bitmap
2d. on the bitmap parameter (select again the small "m" and paste the diffuse map (1)
2e. under UVW transform. (set u and v scale set between .1 to .01 for the start) i found if i set them to 1 the map applied in the surface os too small)
2f. then click apply.
2g. under map. check the bump tick box and press the small "m" on the right of this tick box
2h. choose type bitmap. this time the same step as (2d) paste your bump map(2) under uvw set u v scale the same as your diffuse map. then click apply.

[valynkenlyl]

Re: linked material and bump map issues

Here are three images to more clearly describe my problem. As you will see my problem arises from the act of linking a vray material to a sketchup material via the vraylinked material. I want to be able to use this method for the obvious reasons of being able to see the tiling of the material in the scene. Using vray materials only and relying on test renders to tweak material scale and placement is not an efficient workflow.


First image (initial render all is well)

Second image (Render right after applying vray_linked material, ) note that no changes have been made to the diffuse settings of the map within sketchup material editor, Also the diffuse channel of the linked material in vray is read only. Also map channel is 1.

Below that is the third image which is using only a vray material, without use of sketchup material assignment at all. Here everything works as expected. ( only problem is the inability to dynamically adjust and see adjustments of materials in real time.

So it seems my biggest problem is the apparent inability to get linked materials to work as others seem to be doing, can anyone see what I am doing wrong from these settings?










AGAIN THANKS TO ALL WHO HAVE POSTED THE GREAT COMMENTS THUS FAR any additional feedback or ideas would be appreciated.

Thanks

[dcauldwell_cg]

Re: linked material and bump map issues

Valynkenlyl

The plot thickens!

At first I couldn't re-create the effect you have on the brickwork, but I know that something similar has happened to me before.

Then I tried applying a colour (grey) to some faces using sketchup materials, and then applying the linked antiq... using the vray material editor (ie right click on material, apply vray material, apply linked antiq...)
Then when I rendered I got this (the clashing materials are on the inner faces)



I then (in sketchup) re-applied the antiq... and it rendered ok.

So, maybe the problem is caused by clashing materials :-\
ie one material applied in sketchup and another in vray.

I also, inadvertantly, applied the linked material to the 'floor' and whatever I do I can't apply 'none' using the vray material applicator. When I select 'none' ie no vray material, it just re-appears next time I click on it - and it renders, even when I try applying a different sketchup colour :'(

I am now in uncharted waters - help !!!!

David

[nomeradona_cg]

Re: linked material and bump map issues

ok we need another ruby script here. deleting all applied vray materials. and maybe all the lights too. something like resetting everything as if you did nothing in vray.

[dcauldwell_cg]

Re: linked material and bump map issues

Valynkenlyl

Going back to the loss of texture, I think you would get the same effect if the .jpg texture file was moved and couldn't be found by vray - you then just get a solid brown.

David

[valynkenlyl]

Re: linked material and bump map issues


So I FINALLY found the nuance that was giving me fits. It gets kind of complicated but I will do my best to explain

In a nutshell the problem seems to be within how you apply the initial sketchup material to the object.

METHOD 1 IN all my previous attempts I was applying the material at the group level not to individual faces. If I repeat this process:
1. create cube and group it.
2. apply sketchup brick material to entire group
3. add vary linked material to sketchup material

I get the same result I showed before where the material goes all screwy in the scale department. Shown with the browning foreground box in image below

METHOD 2 IF I however take a different path:
1. create cube do not group it.
2. apply sketchup brick material to each face of cube individually.
3. add vray linked material to sketchup material

I get the intended results, the material continues to render and scale as you would expect. As shown in the rear box with the cutout in the back of the image below An additional note here is that once this initial link has been made, additional applications of this material with its linked vray material continue to work on objects regardless of if the material is placed at the object, or face level. This is illustrated by the smaller foreground box on the left of the image.

So it appears that when you first apply the sketchup material, you are also potentially generating a UV data for vray. and if you do this at a group level, vray appears to have difficulty resolving the UV for the linked read only diffuse level of the material

Hope this makes sense. =Again the image illustrates the issues, the large box in the back is done via METHOD 2 above, the one on the left rear with correct texture is application of map from Method 2 to a grouped cube and the foreground box w/ the messed up texture is method 1

I would be interested if you both have the same results..

Thanks again for following this post. If you have the same problem, would you guys consider this a bug, or just a workflow nuance?

[joe_b]

Re: linked material and bump map issues

I'll have to test that UV issue with groups. Thanks for breaking your process down for me in such detail, that should make it very easy to trace this down.

On another note- I have found a bug in my recent travels where uv information is messed up when applying to the back of a face. I've fixed that in my development build - I'm not sure if that may be to blame for some of these problems or not.

[dcauldwell_cg]

Re: linked material and bump map issues

Yep

I got the problem the same way. And yet when you explode the group the texture scale is corrected. Wierd.
- another one to remember!

[valynkenlyl]

Re: linked material and bump map issues

Joe

All my material applications are to the front face (sketchups tan face w/ the default material no the blue one) So I do not think this has to do with the backface issue that you speak of.

[joe_b]

Re: linked material and bump map issues

All my material applications are to the front face (sketchups tan face w/ the default material no the blue one)

Ok - either way I'll check out the group uv issue and see what I can figure out. Thanks

[nomeradona_cg]

Re: linked material and bump map issues

this is precisely what im saying. because i had the same problem. that is why i always said on my previous post to apply the texture on each face one at a time not in group. its a bit pain staking. maybe joe can look at applying it in group it's much better.

this actually what also happen to my bump maps.