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A couple of questions
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A couple of questions // Work in Progress
Post by Maldrachen // Aug 13, 2008, 2:03am
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Maldrachen
Total Posts: 49
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Hi i have a couple of questions regarding TS.
1. i seem to have a recurring problem with patterns repeating / appearing in ground textures, is there an easy way to solve this? i guess i could shrink all the scene components down in size but that seems a tedious process.
2. as u can see in the image even with an image selected as a background it doesnt appear in the reflective surface of the tank, is this normal? or am i missing something :) ( wouldnt surprise me ).
thanks
http://www.iwerx.com.au/files/pipeworx1024768txt.jpg |
Post by rrf // Aug 13, 2008, 2:48am
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rrf
Total Posts: 319
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For #1 - I could be wrong, but it looks to me like the base texture you used may not be quite as seamless as it looks. It looks like it might have a slight darkness at some of the edges, and when you increase the UVs to fill the area, you get the checkerboard effect. The 'bump map' looks ok, though. Maybe check to see if the texture is built with layers?
hth,
rf |
Post by Georg // Aug 13, 2008, 3:12am
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Georg
Total Posts: 270
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The tiling effect of your groundtexture is not so bad. looking at the bump tiling it must be a checkered texture to begin with. I do not understand your question about the reflection. The ground can never be reflected in the tank with the position of the tank and floor the way it is. Unless you have the texture as backgound picture, then you might see it back, but that would not be very nice.
Very nice picture BTW, a small hot tub?
You could add some HDRI to the lighting to make the reflections on the pipes even more interesting.
Georg |
Post by rjeff // Aug 13, 2008, 3:43am
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rjeff
Total Posts: 1260
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What he may be referring to George is the fact that he has a background image and it is not being refelcted in the sides of the tub..it is just black. What type of background are you using? Are you using a HDRI image or just an image set as a background? |
Post by TomG // Aug 13, 2008, 4:14am
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TomG
Total Posts: 3397
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An image set as a regular background image cannot render in raytraced reflection as refraction. This is because the image is not "really there" in the scene, and the rays have no way to know which part of the image they are hitting, as it is not wrapped around the scene.
An HDRI background image is different - since it wraps around the scene, the rays can figure out which part of the image they are hitting, and so figure out what to show in the reflection.
The other alternative to using HDRI is to place an actual object in the scene, enlarge it so it encases the whole scene, ensure it renders double sided (or invert the normals if you want to keep it single sided), turn off shadow casting and shadow receiving for it, and then paint it with your background image. This is a skydome (or sky cube if you go that route) - now the rays can calculate where on the image they hit as they have a real object to intersect with.
For the repeating ground, it looks like your texture image is not seamless - the left hand edge of the image does not meet and match accurately the right hand edge of the image, and the top does not accurately meet the bottom. When an image is not created specially to be a seamless texture, then you will see each repeat of that texture as a "square" on the object.
You don't need to scale everything down, you can just set the repeats to 1 to achieve the same effect, btw. This will just use the texture once, and you won't see the edges repeat, but it may not give the result you are looking for (since this texture covers a wide area, if it is not a large image size in terms of pixel width and height, you'll see distortion and possible the pixels from enlarging the texture image in the final scene - a rule of thumb, the texture should be at least as large as the pixel size it will occupy in the final render, if you are not repeating it in the material editor).
Note that even when seamless, the eye is VERY good at picking up patterns, so when duplicated many times as done here, the eye may still spot the repetition. In these cases it is best to repeat the image 2x2 or 4x4 or more in a 2D application, then add some more noise and variation on top of that, then ensure it is still seamless, then save the image - this will mean you have a larger texture to repeat, needing less repetitions in tS, and with more variation.
HTH!
Tom |
Post by Georg // Aug 13, 2008, 4:30am
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Georg
Total Posts: 270
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I see. The bitmap has many (MANY!) UV repeats and the bump only few. I must say I like the patterned effect it gives, really a bit like industrial flooring.
georg |
Post by Davin // Aug 13, 2008, 4:00pm
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Davin
Total Posts: 59
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Ok, here are a few things.
1) A quick and dirty way to get less visible repeats on your textures:
UV repeat a lot.
Make a mask of random black to white.
Add a new layer to the texture and repeat the texture less using the mask.
In the first image you can see I have a big square with a checkered pattern layered with a mask and the same texture repeated less.
Next up are two smaller squares with a rock texture that does not repeat well as seen on the right square.
Using the same texture and the mask I used on the big square the texture on the left looks much less repeated.
2) Reflecting an image
Quick n' Dirty:
For the sphere I used the environment material while keeping reflections.
the problem with this way is that the image will bleed onto things you probably do not want it too, you can see the the bottom of the sphere is orange when it should just be reflecting the squares below it.
Better but more time consuming:
A better way is to use a sky box or if you are not going to be panning up or down, then a cylinder.
Use the constant reflectance shader on the sky box and take away is shadow receiving and casting.
In the second image I used a cube for my sky box, but as you can see on the sphere a box can cause some seem problems, you can use the same technique with a cylinder but I find that an octagon shape is enough even when using the same 6 textures. Oh yeah, Make sure you flip all the normals of the sky box object.
The third image is the mask I used in my examples, you might want to make your own random one depending on the size of the surface it is going to cover. Bigger area means you want smaller black and white areas. |
Post by Maldrachen // Aug 13, 2008, 7:24pm
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Maldrachen
Total Posts: 49
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Thanks guys, there is some excellent information there, im going to start trying the solutions out now, thanks again |
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