Textures

[dejan_malenic1@hotmail.co]

Hi,

2 questions about textures:

1. I found some useful materials online and would like to use them in vray for rhino. the only problem is that they have bitmaps that seem to rescale themselves depending on the size of the surface i appy them to. Is there a way I can set the scale? In particular there is a brick material I want to use and when I apply it to a five story building it looks like the bricks are 5 feet high, how can i scale it so that each brick is a particular size?

2. is there a way I can change the color of materials like this while still keeping the original bitmaps and bumpmap? ie. I just want to change the color of the bricks.

thanks for the help

[frip51]

Re: Textures

Dejan,
welcome to the ASGVIS forums
To answer your questions briefly:
1. Unless you apply a texture mapping channel via the Object Properties settings (select the object, press [F3]-key and choose Texture Mapping from the drop down menu) the UV-coordinates of the object will be used to place the mapping. How to handle the Texture Mapping channels? Simply see pages 43-47 in the V-Ray User Manual.

2. Usually, you need Photoshop or the like to change a bitmap colour properly. But there's a way using the Blend type instead of just Bitmap type from the Texture editor: Setting one of the texture slots to Bitmap and the other to AColor lets you tint the texture however you want. Playing around with the Multiplier and Gamma values of the Bitmap allows you to set the desired saturation for the tinted image.


Hope that makes sense

Cheers,
Matt

[dejan_malenic1@hotmail.co]

Re: Textures

I did try to change the color using photoshop. I simply put a mask over the image and flattened it and saved it under the same name. when i tried to import it into vray it came out the same as it looked before (same color). Do i need to re apply the bitmap or something?

[frip51]

Re: Textures

Dejan,
yea... good one! It's a little annoying that V-Ray appears to pre-load the image so that any changes that are made after applying it to a texture are not recognised.
Try to save changed bitmaps with different file names and assign those to the material. That should do the trick

[dejan_malenic1@hotmail.co]

Re: Textures

Ok, so I have still dont know how to resize the textures. Right now no matter what numbers I put into the "size" tabs under texture mapping the image renders the same. I am using Planar projection. Right now I have a bitmap with a certain number of bricks and I want to repeat that pattern to have more brick over the surface of my building.

[**dubs**]

Re: Textures

Ok, so you're using planar mapping . . . there is two ways to change the 'tiling' of that map. . .

- Through Rhino. . . You're mapping widget should share the same proportions as your bitmap i.e. if you're texture is square, your're mapping widget should be square too . . . you can adjust this in Texture Mapping>Size, its always easier to tick the 'show advanced UI' box and click on the 'Show Mapping' option, that will make the mapping widget visible in the viewport (but not in rendered viewport)

In the same properties window which you assigned planar mapping you have UVW repeat at the bottom, at default it will be U= 1.0, V=1.0, W=1.0, if you changed that so U=2, V=2, you should be able to see the texture change in the viewport? (W will be fine left at 1.0).

In principle you're mapping widget should be the same size or slightly bigger than you're object but have the nominal proportions of the bitmap (i.e. square or whatever) and the tiling is controled with the UVW repeat numbers.

- The second one is through Vray! it is found in the material properties, wherever you have the bitmap applied (big M) you'll have U,V repeat and mirror options. . . you need the texture assigned to 'Texture' and 'Explicit Mapping Channel> 1' usually. This way you are shortcutting the UVW part in Rhino (above)


In a visual profession (which most, if not all of us are) I'd argue this is counter intuitive . . . Its not easy, you have to type numbers into an interface until you can see the result you want in the viewport. . . Its a bit like peeling an orange through a letterbox!?

Hopefully we will have a better, more intuitive interface for texture mapping in Rhino 5!

Hope this helps,

Stu