Strange SunBeam

[kc1]

with this simple code (no objects, only sunlight) can obtain a strange beam of light from sun. Version 6.6 (but 5.7 also)

Code: Select all

<scene>
	<renderer_settings>
		<width>400</width>
		<height>300</height>
		<metropolis>true</metropolis>
		<large_mutation_prob>0.1</large_mutation_prob>
		<max_change>0.02</max_change>
		<max_num_consec_rejections>1000</max_num_consec_rejections>
		<bidirectional>true</bidirectional>
		<russian_roulette_live_prob>0.7</russian_roulette_live_prob>
		<max_depth>1000</max_depth>
		<strata_width>14</strata_width>
		<logging>false</logging>
		<save_untonemapped_exr>false</save_untonemapped_exr>
		<save_tonemapped_exr>false</save_tonemapped_exr>
	</renderer_settings>

	<tonemapping>
		<reinhard>
			<pre_scale>2</pre_scale>
			<post_scale>1</post_scale>
		</reinhard>
	</tonemapping>

	<skylight>
		<sundir>0.000000 1.000000 -0.000000</sundir>
		<turbidity>2.000000</turbidity>
		<sky_gain>0.005000</sky_gain>
	</skylight>

	<camera>
		<pos>14.299187 -28.384285 28.820198</pos>
		<up>-5.799472 12.520470 36.677795</up>
		<forwards>-15.415677 33.280880 -13.798404</forwards>
		<aperture_radius>0.001000</aperture_radius>
		<focus_distance>2.000000</focus_distance>
		<aspect_ratio>1.33333</aspect_ratio>
		<sensor_width>0.035000</sensor_width>
		<lens_sensor_dist>0.038281</lens_sensor_dist>
		<white_balance>D65</white_balance>
	</camera>

</scene>

[OnoSendai]

Your sun is at the horizon, and the bottom half of the env sphere is filled from the horizon, so the sun is getting stretched down