import environment failure in blender 2.8 and better lights

[Alessandro Padovani]

tested with daz studio 4.12.0.86, blender 2.82, plugin commit 8285adc

It seems the plugin can’t import a rotated environment anymore. I get the error reported below.

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The whole lights discussion for implementation is in the old tracker #181. Below an example with dome xyzr = (15,30,45,5) and intensity 2 for quick reference. First iray then cycles.

https://bitbucket.org/Diffeomorphic/import-daz-archive/issues/181/importing-the-hdr-environment-and

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[Alessandro Padovani]

I also checked the lights imported in 2.8 and there are a number of issues. The full reference is always in the old tracker #181.

https://bitbucket.org/Diffeomorphic/import-daz-archive/issues/181/importing-the-hdr-environment-and

1) For point and sphere lights it is wrong to export two lights for double sided, since in daz studio it makes no difference. The double sided attribute only works for rectangle and disk lights where the light gets a flat surface.

2) For the point light the 5x multiplier seems no more necessary in blender 2.8. I guess they fixed it. So the strenght formula is the same as the other lights.

iray light type = point light or linear point light
iray photometric mode = on
iray light geometry = point

cycles lamp = point
cycles size = 0
cycles strenght = iray luminous flux / 15000
cycles color = iray color

3) The iray disk light has to be implemented as an area light with disk shape in cycles. Actually it is implemented as a point light with radius. The difference is that the point light with radius is actually a sphere, not a disk. I guess the disk area wasn't available in blender 2.7 when we first exported lights.

iray light type = point light or linear point light
iray photometric mode = on
iray light geometry = disk

cycles lamp = area disk
cycles size = iray height
cycles strenght = iray luminous flux / 15000
cycles color = iray color

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[Alessandro Padovani]

There’s another issue with lights.

4) The cycles strength in the equations above is used both in the strength and power channels in blender 2.8. This is wrong because effectively multiplies the strength by the power. I guess this confusion is due to the fact that in 2.7 there wasn’t a power channel, that is, the power was implied at 1W. In 2.8 it is better to use the power channel that’s more meaningful, and leave the strength at 1.0.

Below an example with correct values where 45000 lumens in iray get converted into 3W in cycles.

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[Alessandro Padovani]

Commit f1a9b48 is ok for the hdri environment and also fixes 1 to 3 for lights. It doesn’t fix 4. Please let me know if there’s any reason so I’ll mark as resolved or close. Otherwise I’ll wait for 4 to be fixed.

[Thomas Larsson]

Should be fixed now.

[Alessandro Padovani]

Commit 13ca5c9 seems fine, marking as resolved. Thank you Thomas for the quick fix lights are back :)