Lighiting problem

[Dick Lai]

Hi everyone

i would like to ask how can i change the lighting unit from cm to mm??

because the materials n the drawings unit are mm..

it takes a long time to convert.

thank you guys!!

[Roy Hirshkowitz]

I'm not exactly sure what you're asking but I'll try anyway.  If I'm on the wrong track let me know.  

The model units must be set correctly in order for nXt to work properly.  Use the AutoCAD _UNITS command to guarantee that the drawing units are correct (the _INSUNITS system variable does the same thing.) Once you do this, materials should appear at the correct scale and the lighting values will be correct.  More info is available here.

[Dick Lai]

thanks for your answer,

for example,

when i use  for the drawing unit,

the lighting setting is 40watts

when i use , it will change to 0.04watts

how can i use mm and normal watts?

thank you
 Roy Hirshkowitz said:

I'm not exactly sure what you're asking but I'll try anyway.  If I'm on the wrong track let me know.  

The model units must be set correctly in order for nXt to work properly.  Use the AutoCAD _UNITS command to guarantee that the drawing units are correct (the _INSUNITS system variable does the same thing.) Once you do this, materials should appear at the correct scale and the lighting values will be correct.  More info is available here.

[Dick Lai]

Roy Hirshkowitz said:

I'm not exactly sure what you're asking but I'll try anyway.  If I'm on the wrong track let me know.  

The model units must be set correctly in order for nXt to work properly.  Use the AutoCAD _UNITS command to guarantee that the drawing units are correct (the _INSUNITS system variable does the same thing.) Once you do this, materials should appear at the correct scale and the lighting values will be correct.  More info is available here.

[Roy Hirshkowitz]

1. It's very difficult to compare ar4 and nxt.  The raytracer in nXt is much faster (~ 4x) but the product calculates much more stuff than ar4 does so it can take longer depending on the setting. 

2. Changing the AutoCAD units should not change the brightness of lights in watts.  The watts should remain constant.  If it's really changing, I'll need to take a look at your drawing. (See below.)

3. nXt has an internal unit of meters.  For example, the tile size of a bitmap is always kept in meters internally.  They're always expressed to the user in terms of current drawing unit, but the material itself is independent.  A material which is created in mm should work perfectly in a drawing whose units are cm or inches (for example.)

I'm willing to take a look at any of your drawings if you'd like me to.  I am out of the office until Thursday, so I won't be able to do anything about it until then.  You can upload a file here-- include any instructions I'll need to reproduce the problem.