scaling texture on material - trick

[frankbond30]

Hello there,

I always have troubles scaling my texture bitmaps to the material I chose in Rhino. For my designs, I often use books that need a front and back cover; the bitmap files that are used as images for the covers either came out too big, or too small. Adjusting the right scale to a bitmap can be a real pain in the ...

Now I think I found a trick, at least for my books, so that the cover will always come out 100% right (right scale, right size, etc.);

in the texture dialog, after you chose a bitmap file, you probably need to rescale it somewhat. Now when you choose V:1, U:1 or i.e. V:5, U:5, you'll often get a distorted image.
BUT, when you choose V:3, U:3, it miracously resizes perfectly!

If you want to see an image of what I mean, please feel free to ask!

[Micha_cg]

Re: scaling texture on material - trick

I'm not sure I know what your problem is, but some short infos:

* mapping can be done:select object -> Rhino object properties -> mapping

* per default polysurfaces use packedtextures and Rhino know the commands unpacktexture

This both methods change the basic Rhino uv coordinates.

* the VfR material uv manipulation based on the Rhino texture coordinates

[dalomar_cg]

Re: scaling texture on material - trick

Also, if you explode the polysuface and set the mappings for the front and the back individually, the maps should map correctly the first time (assuming the surfaces are not trimmed). After you set the mapping, group the surfaces and you should be fine.

[frankbond30]

Re: scaling texture on material - trick

Hi guys,

thanks for the quick replies! I don't have a problem, more like a revelation! I will go and post some picture, so you know what I am talking about. I don't map using Rhino, since it's not really a texture, but, as Dalomar said, a front and back cover. In 30 minutes I will show what I mean.

[frankbond30]

Re: scaling texture on material - trick

Ok. So for the next renders, I have taken regular book covers from the internet, which have all have a standard book size cover. All books I have used are exploded surfaces, so (as Dalomar said) I use the back and front surface to orient the book cover on.

When I use a 1:1 scale (meaning: U:1, V:1), you would think that the image would be automatically resized to the surface of the book to get a good result, but what you will get is this:



You see that the scale is messed up and the cover is not placed correctly on the surface.

Now when you try to repeat the image 2 times (U:2, V:2), you will get this:



For 4:4, this is the result:



Which is again, messed up and not correctly mapped.

BUT! If you use a 3:3 scale, it will look like this:



The mapping is perfect and the cover is used 100%!! Exactly right.

Why is this?!

[Micha_cg]

Re: scaling texture on material - trick

If I understand right, the book has strange uv coordinates and you correct it by strange settings. If you use the Rhino render, so you get the first same result? If yes, than the uv coords of the book object are the problem or Rhino does something wrong.

You could fix the strange uv coords by apply a planar rhino mapping. Sidenote: if I remember me right from my experiments - export the objects as obj and reimport it and the books should be without a mapping widget, but right mapping, the rhino mapping uv coordiantes are burned in for later use.

[han3d]

Re: scaling texture on material - trick

nice book covers

[Sando]

Re: scaling texture on material - trick

I do a lot of texture mapping and I have found that using Rhino's advanced texture mapping under properties where you can choose different methods of texture mapping and also show the boundries of the texture mapping is very useful.

ps. I can't seem to upload images, otherwise I would of shown you what I mean.

[frankbond30]

Re: scaling texture on material - trick

I do a lot of texture mapping and I have found that using Rhino's advanced texture mapping under properties where you can choose different methods of texture mapping and also show the boundries of the texture mapping is very useful.

ps. I can't seem to upload images, otherwise I would of shown you what I mean.

Yeah from most comments I get the idea that it's a lot better to texture-map using rhino itself. For my next project, I will try this. can you maybe upload the image later on? I'm curious about your settings... thx!!

[Sando]

Re: scaling texture on material - trick

Yeah from most comments I get the idea that it's a lot better to texture-map using rhino itself. For my next project, I will try this. can you maybe upload the image later on? I'm curious about your settings... thx!!

Sorry about that frankbond3 I didn't mean over do it. I've just been told how I can get images on here so I will do it some time today when I get up. ;D

[Sando]

Re: scaling texture on material - trick

frankbond3,

Here are some images that you asked for. Hope they help you...

[frankbond30]

Re: scaling texture on material - trick

frankbond3,

Here are some images that you asked for. Hope they help you...

Thanks a lot for these images! this will help me to improve my texture mapping.
Thanks again.