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I will volunteer my thoughts on backdrops in ray

traced renderings. Backdrops in PBR's behave 

entirely differently and can cause unexpected 

effects on the outcome.

 

Backdrops certainly make a difference in ray trace

quality but have very little effect on rendering time.

They are after all just image files. The higher the

quality of the image you turn into a backdrop, the 

better it will look in the rendering.

 

To have a backdrop or not will depend on your

intended results. If it's just the view out of an

unimportant window in an interior scene, maybe

a backdrop will just be a distraction from your

intended focus. In other cases the background 

is everything. As below. B)

 

Plan View

1622221264_UFOPlan.thumb.png.cb847fd95a1fd29b58f7a0e2ec302662.png

corresponding Ray Trace

UFO.thumb.png.30c78faac28c5bafaa3dbac52dae6421.png

 

  

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hanks for your reply.. your space man without the backdrop would not have the same visual effect for sure!

I am currently working on a house exterior and plan on implementing it into the street view so client can see is house in comparison to his neighbors. 

So what your saying is in RAY TRACE  the backdrop (if a quality image) will affect the quality of the overall rendering but not take up any additional time .  unfortunately I can't  use  material definition on the backdrop if it is not of good quality

again it is a matter of choice

 

can you tell me if there is a specific way to get quality street views into CA for backgrounds

 

 

Thanks

Levina

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Hi Levina. What the little green guy is showing

is the effect the backdrop can have on the model.

In that plan we have the model (in this case the

saucer) and no other objects. The saucer has a

100% reflective surface but there is nothing else

in the plan to reflect except what might be in the

backdrop. Everything that is showing on the skin

of the UFO is a reflection of what is in the backdrop.

It's interesting that the reflected effect wraps all the

way around the saucer like a Spherical Panoramic

View even though the backdrop is flat.

 

Anyhow, in the situation you describe the challenges

will vary depending on the type of view you are

creating. But whether it be an overhead or street

level view the process involves getting a good quality

photo of the existing situation from the viewpoint you

want and then recreating that viewpoint in the camera

view in your plan. As Glenn mentions above (nicely

done BTW) it helps to have an image editing software

program to tweak your backdrop image to suit your

needs. Once you have an image you want to use for

the backdrop open your Library Browser and right

click on your User Catalog. Then go to New and then

Backdrop to add your image to the list of backdrops

you can choose in the camera specification DBX. Of

course there are many other considerations to deal

with such as matching the sun angle shadows and

how much, if any, of Chief's terrain to include and how

it blends into your backdrop image. 

 

Good Luck, hope this gets you started.

 

 

 

 

 

 

 

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9 hours ago, glennw said:

I don't think you can get a good 3D effect by only using a background.

This is a very old one.

 

Nicely done Glenn. Though a backdrop is a pic there's a big difference when the model is incorporated into the pic versus just being in front of the pic. To obtain the former you will need to utilize other software to accomplish this. My example below was done using Photoshop, the CA render was cropped to isolate the structure and added as a layer over a real pic of the site. The model layer was then manipulated in an attempt to match the angles and perspective of the site pic, not perfect but much better than anything that I could have done is just using CA. What's also interesting is that this CA render on it's own looked much less real than after placing it into a real pic. It does beg one to seriously consider whether CA's difficulty in producing convincing renders is related to lighting or just the fact that the symbols we have are just too basic and no matter how well you try to light them they will never look real.

 

398112017_PhotoshopA1.thumb.jpg.327ab6d6cb3708dcebf8b30cda10b34e.jpg

 

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Here's another example just using a google street view rendered in CA. The google street view was first loaded into Photoshop and everything other than the structures were erased. In CA I used a standard sunset library backdrop to provide the sky effect. In the plan I placed a large psolid placed behind the model and used the cropped google street view as a texture. The psolid allowed me to manipulate the google street view to match the camera angle and I could use the texture offset controls to shift it and scale it. The psolid could also be moved forward or backwards to help obtain a sense of depth.

 

368302808_NightStreetView2copyMS1200.thumb.png.b661a3df606e74973fa3c51ab665fb1d.png

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