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blamejane
01-06-2008, 10:06 PM
I was hoping you guys wouldn't mind offering your feedback on my progress...

I decided to model and texture a piece where I had access to reference images of the actual finished product. In doing so, I can see there's still a lot of work to do.

I used a texture from cgtextures.com and added a spec and very slight bump. I'm using area shadows to best simulate the look that softboxes give. I'm also using the default renderer as it supports the area shadows (max 7). In pp I used an occlusion pass and set the blend to multiply. This gave the piece a bit of punch.

I did included a poly object to serve as a back-drop; which I was hoping would simulate the piece being photographed on seamless background paper. The backdrop object has been assigned a standard gray shader.

http://www.imontana.net/3ds/example-model.jpghttp://www.imontana.net/3ds/example-real.jpg

blamejane
01-07-2008, 12:02 AM
As I look at these two pics, I just wonder if it is even possible to make the model look as real as the actual piece.

I would love to see an example of a scene that included a piece of wood furniture, where you couldn't tell the difference. Can anyone provide a link?

Marcel
01-07-2008, 06:12 PM
Don't fret, it's looking pretty good! You've got the model nailed, which helps a lot with the lighting phase.

One thing that strikes me is that in your reference photo the specular highlights are desaturated (white or gray) and in your render they are yellow or brown. A coloured specular gives the impression of a metallic material (like gold, brass or copper).

Another thing is that the light in your scene comes from the front, and in the photo is somes slightly from the left side and a bit higher as well. (most noticable on the round legs).

Keep in mind that the specular is a fake way of creating highlights. The highlights in the photo are soft reflections of the bright lightsource. This means that the size of the lightsource has an influence on the shape of the highlights. I don't know if the size of the area-light also has influence on the highlights in your render engine. If so you could try to make the area light a bit bigger but slightly less strong. I say this because the highlights on the front of the seat are a bit bright and less wide than in the reference.

The texture of the wood has more contrast in the reference, it has more darker and lighter parts. It's colour is also more red on the photo, while your texture is more yellow and more saturated. This could be your design decision ofcourse :)

The darker top of the background in the reference photo also brings out the shape of the chair more.

It's all nitpicking, but with these photorealistic renders it's the details that matter (and take the most time :scream: ).

blamejane
01-07-2008, 09:48 PM
Thanks Marcel...and thanks for the referral to cgtextures.com as I originally found this link from your signature.

The choice of wood was not a design choice so much as it was just the best of those found in the fine wood section. I do wish I could have used the same wood (oregon black walnut) as the actual piece, but in the end I liked the chestnut texture for its long wide boards.

I really appreciate your comments and will tackle each of them to improve my piece. Regarding the left front lighting you mentioned, how do you know that it's higher? I tried to see where I could detect that. Anyway you are correct, I was just wondering how you could tell.

blamejane
01-08-2008, 03:58 AM
Here's the result after turning off one of the front lights, and moving the other up and to the left. I did not use a specular color map, so the yellow highlights are just the results of my lighting and the diffuse texture color (i guess). But I wanted to try to make them white (like the reference photo) and can't seem to manage this. I created a white specular map and added it to the spec color map slot. It doesn't look white to me. I guess I could try changing from blinn to phong, but haven't as of this update. I think the piece looks better, but I really would like to add a layer of finish. Does this make sense? I mean, we add 5 coats of tung oil and polyurethane, then several layers of wax to our furniture. I don't think this piece has that look. Should I create a multi-layer shader or should I try a reflection map?

Anyway thanks.
http://www.imontana.net/3ds/example-model2.jpg

Marcel
01-08-2008, 09:11 AM
You can try to make the specular colour a light blue-ish tint such as RGB: 159 198 229 to counter act the brown/red in the diffuse colour. The result should be more white.
I'm not sure if this works, but this is a trick that I've used in Skin shading where you have the same problem (specular picking up too much of the diffuse colour).

To get a perfect specular you could try to use real reflections instead of a blinn shader. The problem is that you need *soft* reflections, and these tend to take a lot of rendertime. More rendertime means that it is harder to tweak. See if it works, but don't spend too much time on it because it might as well take too much rendertime to perfect.

What you basically do is:

- remove all specular from the shader
- give the material a low raytraced reflection (20% or perhaps even lower)
- make the reflection soft (not sure about the details on how to achieve this, it depends totally on your renderer)

Then you have to setup virtual 'whitecards' or softboxes in your scene at the same position as your light so that the reflections has something to reflect.
Create a white material with 100% self illumination. You might need to crank up the brightness of this materialto beyond 100%, you can do this by typing in the number in the color picker somewhere. The slider stops at 100% or 1, but you can type in 2 or 5 or even more to get a super intense material (just like a real light would be).

Getting the whitecards strong enough is important because otherwise the reflections wouldn't show up as much as they should. If you would make the materials reflection value stronger then the environment would show up too much in the reflection. It's all a delicate balance. :D

Regarding the left front lighting you mentioned, how do you know that it's higher? I tried to see where I could detect that. Anyway you are correct, I was just wondering how you could tell.

I saw this mainly by the top of the backrest. In the photo it's specular is right at the very top, and in your render it is a bit lower with a darker line above. I could only tell because you placed the two images next to eachother in exactle the same position, otherwise I would never have noticed.

Also add a little bit more ambient light, some parts of the chair are 100% black, whereas in the photo it never drops below a certain colour. (the underside of the armrests)

In Photoshop try applying a Hue& Saturation layer on your texture with the following settings:
Hue -5 (a bit more red)
Saturation -20 (less colour)
Lightness 0 (the same)

When wood has too much colour it tends to look unrealistic in my view (any natural material for that matter).

It's a pretty wicked chair by the way, is it a famous model?

blamejane
01-08-2008, 12:43 PM
Wow thanks marcel, I'm going to give this a try.

- give the material a low raytraced reflection (20% or perhaps even lower)


not sure how this is done...do you mean using a raytraced material? Or a raytraced map?

Create a white material with 100% self illumination. You might need to crank up the brightness of this materialto beyond 100%, you can do this by typing in the number in the color picker somewhere. The slider stops at 100% or 1, but you can type in 2 or 5 or even more to get a super intense material (just like a real light would be).

Using Max 7, I'm not sure how to crank up the brightness. The color picker for self-illum uses RGB values only.

It's a pretty wicked chair by the way, is it a famous model?
Thanks, it's my design. :)

Marcel
01-08-2008, 01:15 PM
Wow thanks marcel, I'm going to give this a try.

not sure how this is done...do you mean using a raytraced material? Or a raytraced map?
I'm not sure if the the Max raytrace material or the raytrace map support soft reflections. If not you can always try out other renderers like Mental Ray or VRay.

There used to be a website full of VRay Materials, I think it was www.vray-materials.de (http://www.vray-materials.de/) but it seems to be down now. Check it later, maybe its just temporary.


Using Max 7, I'm not sure how to crank up the brightness. The color picker for self-illum uses RGB values only.
In the colour picker window try typing in a value larger than 255 in the "Value" field. If that is not possible put a white texture in the self illumination slot and make it super bright using the settings in the "Output settings tab".
I don't have Max at hand so I wouldn't know the exact name of the field, but there is one that lets you make your texture brighter. It could be something named 'offset'.

Thanks, it's my design.
Wow, nice work! I'm impressed! Did you also build it yourself?

And how does it sit? :)

blamejane
01-08-2008, 04:59 PM
Thanks again Marcel!

To get a perfect specular you could try to use real reflections instead of a blinn shader.
I know you're not using Max, so I hope I can understand enough to accomplish the real reflections. I've removed all of the specular stuff from my standard material and will try getting a reflection using the reflection map. If this doesn't work I'll try using a raytraced material instead.
try out other renderers like Mental Ray or VRay
Thanks for this tip. I just took a look at vray, which looks great, to bad it's so expensive...ouch. I'm looking at MR now.

In the colour picker window try typing in a value larger than 255 in the "Value" field. If that is not possible put a white texture in the self illumination slot and make it super bright using the settings in the "Output settings tab".
I don't have Max at hand so I wouldn't know the exact name of the field, but there is one that lets you make your texture brighter. It could be something named 'offset'.

I've already tried increasing the RGB which didn't have any affect, so I'll try the white texture for the self-illum map alternative.
Wow, nice work! I'm impressed! Did you also build it yourself?

And how does it sit? :)
My husband does the building, and this one sits excellent! Thanks for asking.

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