[rmulley]

Just a quick question about the scale option....

I have it set on the default at 0.01
But if I chage it to 1 (as everything I have built in FormZ is to scale) the lighting is too dark.

Does Maxwell know what the 'true' distances the model is made in FormZ ?

[Matthew Schrock]

rmulley,

If you have built your model at a scale of 1:1 then you ought to set "Scene Scale" in the "Maxwell Menu" to 1 in order to get realistic results.

The darkness of the image can be adjusted using the ISO, f/stop, and shutter speed settings of the camera.

Yes, Maxwell does appear to simulate light behavior over real world distances - this is a critical factor in achieving realistic simulations.

Matthew

[rmulley]

but what are the measurements used by Maxwell, I read in another thread somewhere about inputting the scale size to match Maxwell.

I work in Inches and other people work in mm.......does MAxwell know this ?


just curious, because I seem to be getting unrealistic results when my scale is set to 1

a regular aperture size, regular shutter speed with 1000-2000w lights still comes out black to very dark.

[Matthew Schrock]

this is a good question - I thought from what I had read in the MaxwellZ documentation, that the plugin gets the units being used in formZ and makes the needed translation to Maxwell units.

Now when I go back and read the most recent documentation it is no longer clear to me.

Juan, can you enlighten us on this question?

Thanks,

Matthew

[rmulley]

I found something in the user manual...

If you are working in FormZ with inches you have to set the scale to 0.0254 (although Maxwell rounds it off to 0.025)

I understand now....Maxwell reads things in Metres.

so a scale of 1 is 1 metre
0.01 is 1cm
0.001 is 1mm

etc

[rmulley]

I was getting some weird results in regard to scale.......a cup I was rendering was coming out all blurred and I couldn't figure out why.

I changed the Working Units in the FormZ Options menu
put the scale to 0.025 in the Maxwell palette and now everything seems great.

Just something people should be aware of.......especially when you're new to Maxwell like me

[rmulley]

sorry I should mention I changed the working units to 'Lamp' in FormZ as I was using 'Building'

I never figured this would make a difference but it seemed to to my render

[Matthew Schrock]

I found something in the user manual...

If you are working in FormZ with inches you have to set the scale to 0.0254 (although Maxwell rounds it off to 0.025)

I understand now....Maxwell reads things in Metres.

so a scale of 1 is 1 metre
0.01 is 1cm
0.001 is 1mm

etc

What you are describing here is exactly how the Max/Viz plugin works - I used that plugin while I was waiting for the formZ plugin. It is not clear, however, that this is how the formz plugin is working. I am doing some tests now to understand this better.

Matthew

[Matthew Schrock]

sorry I should mention I changed the working units to 'Lamp' in FormZ as I was using 'Building'

I never figured this would make a difference but it seemed to to my render

'Lamp' and 'Building' are presets that adjust the numeric accuracy and the number of decimal places displayed - this does not change the units in formZ.

[Matthew Schrock]

This is an experiment to see if MaxwellZ is affected by the working units in formZ.

I made 2 models in formZ - both of them are a 4 unit cube. In the first model the unit is meters in the second model the unit is inches.

In each model I put 1 emitter plane with values set to 65D - 2000 watts.

In the "Maxwell Menu" dialog I set the "Scene Scale" to 1.

Camera settings: f/8, ISO 100, shutter speed 1/100.

Unit set to Meters:



Unit set to Inches:


Observations:
1. MaxwellZ does indeed read the working unit of the formZ model and translates it to Maxwell units.

2. There may be a problem with this translation or with the power setting (watts) of the emitter. Given the camera settings and the 2000 watt light source I would have expected the 4 inch x 4 inch x 4 inch "room" to be over-exposed and the 4 meter x 4 meter x 4 meter room to be well exposed. Instead, the tiny space is slightly under-exposed and the larger space is almost black.

Juan, what are your thoughts on this?

Matthew

[juan]

I would have expected the 4 inch x 4 inch x 4 inch "room" to be over-exposed and the 4 meter x 4 meter x 4 meter room to be well exposed. Instead, the tiny space is slightly under-exposed and the larger space is almost black.Juan, what are your thoughts on this?

Hi Mathew,
as always, your tests are so good and useful. We are checking and fixing some issues with the energy emitted, it seems sometimes there is a bug with scale. Internally, the plugin just multiply all the geometric positions (every vertex and the camera position) by the scale factor you put in the palette field. So if you have your object in (0,0,0) and your camera in (0,0,1) and you put a scale factor of 100, the object will stand in (0,0,0) and the camera in (0,0,100) with the same lens and the same properties, so there will be less ligth from the object to the camera. Of course the initial position of the objects and camera depends on how formZ returns the values to the maxwell plugin, and it depends on the working units (other platforms give the vectors normaliced).

Thanks a lot for your reports. Very soon you will see a so much better maxwell

Juan

[nik_h]

Juan,

I always use mm when working in FormZ and have had no real problems with the scale left at its default value of 0.01. The exposures that I use for my renders are what I would expect to use in real life.

I've just tried changing the scale to 0.001 (which I assume converts 1mm to 0.001m) and the results are very over exposed. To get a sensible image I have to use very unsensible shutter speed and ISO settings.

Am I doing anything wrong here?

Cheers,

Nik

[rmulley]

I've found if you change the working units (i.e building to lamp) it resets the Maxwell scale back to 0.01

just something I noticed that's all

[Matthew Schrock]

From the formZ SDK documentation:



Using this info and Juan's description above as well as the Maxwell documentation that gives the native Maxwell unit as "meter", I come to this conclusion:

When working units in formZ are set to Metric (Millimeters, Centimeters, Decimeters, Meters) the "Scene Scale" in the "Maxwell Menu" box ought to be set to 0.01 - (value in centimeters x 0.01 = value in meters)

When working units in formZ are set to English (Inches, Feet) the "Scene Scale" in the "Maxwell Menu" box ought to be set to 0.0254 - (value in inches x 0.0254 = value in meters)

I will do some more work to test this theory.

Matthew