Jump to content
barkest

Soft and Hard Shadows

Recommended Posts

My default position has always been that soft shadows take longer to render than hard shadows. In Cinema 4D its the opposite way around. Have I been getting it wrong in VW?

 

Quote

Rendering hard or area shadows is much more computationally intensive

 

thanks

Edited by barkest

Share this post


Link to post

I'd question this, would hard shadows make my interior renderings more accurate? In many of my scenes I have a combination of both. If there is sun light present hard shadows it is, if it comes from a distance light bulb then vanishing shadows help.  Does this take longer? I think I'll run a test on this one.

Share this post


Link to post

3 types of shadowing:

Hard=Raytraced, which takes a long time

Shadow mapping=depending on the sample size, can be very fast

Area shadows=takes a long time

 

Hard to know what VW means by "soft shadows." Are they shadow mapped or area shadows?

Share this post


Link to post
2 hours ago, grant_PD said:

Hard to know what VW means by "soft shadows." Are they shadow mapped or area shadows?

 

Looking at the times I would think area shadows, happy to be corrected

Share this post


Link to post

I would guess.  Odd that VW does not allow for shadow mapping.  It's been around for a while. 

Share this post


Link to post
3 hours ago, Luis M Ruiz said:

 I think I'll run a test on this one.

 

Luis,  Perfect time to try that thing we talked about last week. Let me know.

 

Pat

Share this post


Link to post
On 28.4.2017 at 2:41 PM, grant_PD said:

3 types of shadowing:

Hard=Raytraced, which takes a long time

Shadow mapping=depending on the sample size, can be very fast

Area shadows=takes a long time

 

Hard to know what VW means by "soft shadows." Are they shadow mapped or area shadows?

 

 

You mentioned the shadow types :

 

Mapping = fast + inaccurate

Raytraced = not slow + very accurate, but unrealistic in a way that we do not have real light sources with zero size

Area = slowest + accurate

 

Shadow Mapping is soft to very soft, depending on Map Resolution. The problem is

that softness is independent from distance. A pole's shadow will be a soft at its base as for its top.

It is a bit like the 2017 drop shadow effect.

 

Area Shadows softness is dependent on distance from the object casting to the surface, to the surface

receiving the shadow. As larger the distance, the larger the softness area > accurate.

It works a bit like Ray Traced Shadows, just that you need to trace more than 1 Ray (Samples),

from different directions and finally interpolate in some way.

That is why that shadow type ist harder to compute and so slower.

 

So if you watch those soft shadows from VW,

if short shadows are sharper and longer shadows more blurry, those will be true and slow area shadows.

Share this post


Link to post
41 minutes ago, zoomer said:

As larger the distance, the larger the softness area > accurate.

 

My understanding is that the further away the harder the shadow (the sun), the closer the softer the shadow. In addition its not just down to distance it is also affected by the size of the area light. Larger area lights will give softer shadows.

 

 

Share this post


Link to post

Yes,

 

As larger the Light - the softer the Shadow

As farer the distance of the Light to the shadow casting Object - the sharper the Shadow

And,

As farer the distance the Shadow Rays have to travel from the shadow casting Object to the

Object receiving that Shadow - the softer the Shadow.

 

You can take your desktop lamp at an 45° angle and shine on a pencil that you put vertically

on your desk. Where the pen meets the table (=short distance) the shadow will be quite sharp,

while the shadow of the pen top, that has a larger distance to travel is much softer. 

Share this post


Link to post

Shadow Map (blurry everywhere) :

 

Screenshot-14.jpg.a0cb66e567de1aa6802fa2cb47ea66ef.jpg

 

 

 

Raytraced Shadow (sharp everywhere) :

 

Screenshot-15.jpg.b5f454510a51e5e6a11645a1e0c0814b.jpg

 

 

 

Area Shadow (sharp where near, blurry where far) :

 

Screenshot-16.jpg.b5e8d1bbcd7853b613c4fe0514eff196.jpg

Share this post


Link to post

I would prefer that VW incorporate shadow mapping as well.  Area shadows (time) vs raytracing (quality) seems like a lose/lose to me. 

Share this post


Link to post
On 4/28/2017 at 10:52 AM, Pat Stanford said:

 

Luis,  Perfect time to try that thing we talked about last week. Let me know.

 

Pat

I am on it....

Share this post


Link to post

Sorry for the delay, I was away at AIA Orlando booth running 3d and rendering demos, now, we are back and I have something to share. By using Pat's time script I was able to compare the time it takes to render four viewports with the same properties but different lights configurations and two rendering styles. To my surprise, sharp shadows with no ambience lights take very little time compared to a light source with soft shadows. Now, when we get close to produce a better quality rendering we add some environment light and a number of light bounces, here is where the time to my taste is irrelevant, the waiting period was minor.  Here are my notes:

 

 

Test shadows plain.jpg

Test shadows w light bounces.jpg

  • Like 1

Share this post


Link to post

In the second example it looks like an area shadow and the timing supports that.

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


 

7150 Riverwood Drive, Columbia, Maryland 21046, USA   |   Contact Us:   410-290-5114

 

© 2018 Vectorworks, Inc. All Rights Reserved. Vectorworks, Inc. is part of the Nemetschek Group.

×
×
  • Create New...