Question about focus and units

[JeZ]

Hi,
I am new here. I've been reading your posts for some time and I would like to thank you all. It helped a lot.

Now I would like some help to understand how focus work.

I am using sketchup 6, last skindigo version and indigo 1.0.7.

My question is :
Do Skindigo convert units?

If I am modeling in inches, do it convert inches in meters (I think Indigo is using meters)?

I did a lot of tests with box shapes of about 6in x 6in x 12in, with f22 aperture and the depth of field is always very shallow. I am not that good in photography, but i would have guess f22 is enough to get all objects in focus.

So I thought maybe it is related to units, somehow...

Here's an exemple

Jerome

[JeZ]

Hi again,
Since I first posted, I did some tests without obvious success.

There's a list of things I tried :

turning off aperture and post process diffraction,

changing values of nm cubic, but I dont really understand how it works,

I verified my "theory" about units by changing, in sketchup, the model units and it did nothing. So, it isnt related to units.

I tried other setups, but dont remember.

Now, the only other setup I can imagine is changing filters method, to gaussian i think, the one that is supposed to be sharper.

So, this is where I am. If anyone has any hints or ideas, it would be very nice.

Thanks.

Jerome

[cpfresh]

what are you trying to achieve? having the entire block in focus? are you using auto focus or manually selecting a point? i modelled the same shape you have described here and rendered resulting in a smililar image to yours. i was able to improve focus by setting my focus point to about the midsection of the block. then the front and back of the blocks edges were in focus.

[JeZ]

what are you trying to achieve? having the entire block in focus? are you using auto focus or manually selecting a point?

Hi cpfresh,
I want to get the entire block in focus. I selected the corner in the middle of the screen as focus point. I believed the focus point is setting the focus distance between the camera and the focus plane, where the depth of field "begins".

Yesterday, I tried to set filters to gaussian, it was kind of more sharp but the depth of field seems the same.

I guess I need to change the camera settings, like sensor width or maybe aperture shape (i don't know if the aperture shape do something other than bokeh and glare thing).

Does skindigo use the field of view value in sketchup to set focal lengh?

Anyways, thank you cpfresh for your reply.

Jerome

[Pibuz]

..uhm..
just a try: reset camera and then don't specify a focus point. Let f/22, that should work!

[JeZ]

hi,
well after some other testing, it turns out I am the problem.

The focus distance is very short, i did not realized. So the dof is too...

..uhm..
just a try: reset camera and then don't specify a focus point. Let f/22, that should work!

Thank you Pibuz, I think it was part of the problem. Do you know why some settings are not updated when I hit apply changes??

I still have one question. If I want to change focal lengh, how do I do it?
Is it only related to the field of view value in sketchup? It is a pain to calculate focal lengh with field of view angle. I don't even know if it is diagonal field of view angle.

Anyways, thank you all.

Jerome

[Pibuz]

Oh, no no:
the field of view in SU (i find) it's only related to the effective width of your image. So, set your scene with the appropriate zoom value in SU, then in the camera parameters pick your desired f/stop (f/22, f/4, whichever you want..) and choose a focal point by clicking it directly on the object in SU. Now, if you render, you'll have your camera aperture considered, and the object you specified in focus.

[JeZ]

Oh, no no:
the field of view in SU (i find) it's only related to the effective width of your image. So, set your scene with the appropriate zoom value in SU, then in the camera parameters pick your desired f/stop (f/22, f/4, whichever you want..) and choose a focal point by clicking it directly on the object in SU. Now, if you render, you'll have your camera aperture considered, and the object you specified in focus.

hum...
I am not sure I understand. The zoom tool doesn't feel like "real zoom". I don't think it actually change focal lengh, like a real zoom do. So, either the camera has a fix focal lengh, either there is another way of changing it, or it just don't work that way. (?)

When you set your camera, how do you set the DOF? by trial and errors?
How is it possible to set DOF without knowing focal lengh?

Pibuz, I kind of feel attacking you with questions, sorry about that.

Thank you man!

Jerome

[cpfresh]

you're right Jerome, normal zoom does not change the focal length, it changes the position of your camera. the focal length will remain at what ever setting you put it at previously. you can achieve a "real zoom" by using the zoom tool along with pressing the shift key. then when you zoom you can see the focal length changing. hope this helps!

[Pibuz]

NO PROBLEM MAN!

I try to make me clear(er):
1. Using Sketch, as you know, the camera has no dof at all: whatever you see is in plain focus, right?
2. So, while modeling, and then choosing the scene you prefere, the only thing you have to pay attention is what you see and what you don't. Generally, i tend to imagine the future size of the render corresponding to my screen size.
3. If you need to "open" the width of your SU image to see more things, you know, just increase the zoom value. I don't know if that value corresponds to a physical (=real) value in a real camera. However, change the value as far as you can see what you want.
4. Then, time to render. Open the camera parameters, and go to aperture. It should be f/22 by default. Why? Because f/22 corresponds to a very very very little shutter aperture, which guarantees a very long DOF. It also involves that a very very very little amount of light can pass through the camera, so to get a bright image you should have very long exposure times. But if you have Reinhard tonemapping active, it automatically balances exposition and render times, so you don't have to worry about that.
5. If you decide to have something out of focus, just change the camera aperture, and then specify a point of focus.

I hope i somehow helped you!

[JeZ]

Hi,
I did a quick test render on a model I had.
Really not perfect...
There are two "mesh" emitters.

This is straight from indigo.

If anyone has some comments, don't hesitate.

Thanks

Jerome

There are part of the settings in indigo:

SSE present.
SSE2 present.
SSE3 present.
Using base Indigo directory path 'C:\Program Files\indigo_v1.0.8'.
Scene file path: '\\Emachines\SharedDocs\bureau.igs'
Using working directory path '\\Emachines\SharedDocs'.
Loading Scene '\\Emachines\SharedDocs\bureau.igs'...
Processing included XML file '\\Emachines\SharedDocs\bureau-settings.igs...
Using Reinhard tone mapping with pre_scale=4.500000, post_scale=1.000000, burn=6.000000
Calculating energy loss compensation curve for exponent 80.000000
trying to load texture from '\\Emachines\SharedDocs\TX_bureau/noyer.jpg'...
Loaded texture successfully.
Calculating energy loss compensation curve for exponent 500.000000
trying to load texture from '\\Emachines\SharedDocs\TX_bureau/Material2.jpg'...
Loaded texture successfully.
trying to load texture from '\\Emachines\SharedDocs\TX_bureau/Wood_ Floor.jpg'...
Loaded texture successfully.
0 UV coordinate set(s) found.
1 UV coordinate set(s) found.
1 UV coordinate set(s) found.
1 UV coordinate set(s) found.
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
WARNING: Ignoring degenerate triangle. (triangle area: 0.00000E+000)
1 UV coordinate set(s) found.
1 UV coordinate set(s) found.

[...]

Light luminous flux: 1750.00000 lm
Master buffer size: 30.640 MB
Settings:
Splat filter: mn_cubic, blur=0.60000, ring=0.20000
Downsize filter: mn_cubic, blur=0.60000, ring=0.20000
Render region: false
Supersample factor: 2
Metropolis: true
Bidirectional: true
Hybrid: false
Ray origin nudge distance: 0.00010 m
Aperture diffraction: false
Post-process diffraction: false
Auto setting number of threads to 2.
Finished initialisation
Starting threads... (num threads: 2)
Starting render thread. (RNG seed=1206994737)
Starting render thread. (RNG seed=2413989474)
Doing initial warmup.Doing initial warmup...........
Done initial warmup.