A couple questions about Drop Shadow, at least one of which I suspect is not possible:
I have an image (abstract) comprised of similar hues, but many tone/saturation levels, and lots of "shapes", large and small.
1. I tried using the Edge Transform (which worked to distinguish edges between hues/tones) which I converted to a mask, to place drop shadows on the various shapes. However, as expected, the edges created an encircling mask around the shapes which resulted in the shadows also being introduced within the shapes. Without making multiple (and I mean a lot, pretty well impossible) masks, one of each shape, is there a way to do something similar to an Edge but have the Drop Shadow only on one side as if it was a solid mask? (that's the one I doubt is possible).
2. In doing this testing, both with an edge mask around a shape (so a crude circle) and a solid mask (in this case I just did up a quick round shape), when the Drop Shadow is used, it produces a slight shadow on the opposite side of where it is intended. How do I prevent this? I will try and attach a couple images to show what I mean.
3. And a follow-up to 2, I also notice with the circle shadow, the shadow extends well past the spot where the shadow should actually start (ie into the area which should have no shadow). Again can I do something to prevent this?
It appears the images which I wished to send are too large, so if you wish to see them (hopefully my explanations will suffice), let me know and I will resize and send in a follow-up.
Drop Shadow
Moderator: jsachs
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Marpel
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Re: Drop Shadow
Managed to resize:
- Attachments
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- DSEdge.jpg (10.54 KiB) Viewed 918 times
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- DSCircle.jpg (12.71 KiB) Viewed 918 times
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Marpel
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Re: Drop Shadow
First, sorry for the large size of images. I thought they would show smaller.
And, I was just playing around with Drop Shadow on another project and noticed the following:
1. The "back-shadow" I mentioned in the initial post appears to only occur if the mask is freestanding within the image. If part of the mask extends beyond an image boundary the back-shadow does not occur.
2. I also found that if I use a DS with a parameter beyond the default (in my example, I did an Offset of 50), then do another/different mask and try to Reload Last Settings, to get the same Offset - if the new mask is identified first, the mask shows on the image and the new Offset is shown in the Dialogue but the Offset is not reflected in the image (default value is the result). However, if the Reload Last Settings is applied, then the new mask is identified the correct Offset results. Should the Last Settings be applied regardless of the order in which the mask is chosen?
And, I was just playing around with Drop Shadow on another project and noticed the following:
1. The "back-shadow" I mentioned in the initial post appears to only occur if the mask is freestanding within the image. If part of the mask extends beyond an image boundary the back-shadow does not occur.
2. I also found that if I use a DS with a parameter beyond the default (in my example, I did an Offset of 50), then do another/different mask and try to Reload Last Settings, to get the same Offset - if the new mask is identified first, the mask shows on the image and the new Offset is shown in the Dialogue but the Offset is not reflected in the image (default value is the result). However, if the Reload Last Settings is applied, then the new mask is identified the correct Offset results. Should the Last Settings be applied regardless of the order in which the mask is chosen?
Re: Drop Shadow
You could try to flood-fill the edge mask (there is also a Fill tool which does this on images rather than masks).
The Last Settings are the settings from the last time you clicked OK on the transformation. Double-clicking on a slider restores it to the value it had when you launched the transformation.
>> I also notice with the circle shadow, the shadow extends well past the spot where the shadow should actually start (ie into the area which should have no shadow).
This is a result of the blur radius -- the blurred shadow can extend beyond the object. Set the blur radius to 0 if you want a hard-edges drop shadow.
The Last Settings are the settings from the last time you clicked OK on the transformation. Double-clicking on a slider restores it to the value it had when you launched the transformation.
>> I also notice with the circle shadow, the shadow extends well past the spot where the shadow should actually start (ie into the area which should have no shadow).
This is a result of the blur radius -- the blurred shadow can extend beyond the object. Set the blur radius to 0 if you want a hard-edges drop shadow.
Jonathan Sachs
Digital Light & Color
Digital Light & Color
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Marpel
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Re: Drop Shadow
Jonathan,
Thanks for the quick response.
The problem with Flood Fill is the edge mask is not perfectly formed/solid and has "bleed-through" areas which would allow the Fill to spread. But I will play with this idea.
Not sure if we are on the same page regarding Last Settings - if I open the DS Dialogue for the first time, it appears to have a default Offset setting of 10. If I change that to 50, it does so and the DS is correct > OK. If I then open the Dialogue again, with a different mask(2) and the same image, it has the initial default settings (10), which is expected. If I identify the mask right off, then click Last Settings, the red mask(2) overlay is evident on the image, the Dialogue Offset changes from the initial 10 to 50 (expected), but when OK is clicked, the result does not reflect 50 but shows a narrow shadow of 10. The Offset last settings (50) only works if the Dialogues Last Settings is activated first, then the mask is chosen. I'm so used to entering Dialogue parameters from the top down, that by habit in this case it causes the resultant image to not have the new (Offset 50) shadow even though it states so in the Dialogue. I presumed that if the Dialogue shows 50 and the red mask(2) overlay is evident on the image, regardless of order of entering parameters, the resultant image should reflect that.
And the same confusion for the last point - I am wishing to do a blurred (in this case Offset 100, radius 10) shadow, not hard edged. But I find that if the light direction is from top left as an example, the shadow extends towards the bottom right (expected). This works fine on a straight line mask (say from bottom left to top right), but if the object is a round circle in the middle of the image, the shadow slowly fades as it wraps around the circle back towards the direction of the light, however it continues past the point that the light should prevent a shadow from existing. In fact if the background is white and the object is white, one can see a diminishing shadow all the way along the lit side of the circle (a close look at the circle image I posted), which it shouldn't have. Of course the darker the background, the less this is visible. I only noticed it as I was working white on white, but it is still visible on backgrounds which are less dark than the shadow.
Thanks for the quick response.
The problem with Flood Fill is the edge mask is not perfectly formed/solid and has "bleed-through" areas which would allow the Fill to spread. But I will play with this idea.
Not sure if we are on the same page regarding Last Settings - if I open the DS Dialogue for the first time, it appears to have a default Offset setting of 10. If I change that to 50, it does so and the DS is correct > OK. If I then open the Dialogue again, with a different mask(2) and the same image, it has the initial default settings (10), which is expected. If I identify the mask right off, then click Last Settings, the red mask(2) overlay is evident on the image, the Dialogue Offset changes from the initial 10 to 50 (expected), but when OK is clicked, the result does not reflect 50 but shows a narrow shadow of 10. The Offset last settings (50) only works if the Dialogues Last Settings is activated first, then the mask is chosen. I'm so used to entering Dialogue parameters from the top down, that by habit in this case it causes the resultant image to not have the new (Offset 50) shadow even though it states so in the Dialogue. I presumed that if the Dialogue shows 50 and the red mask(2) overlay is evident on the image, regardless of order of entering parameters, the resultant image should reflect that.
And the same confusion for the last point - I am wishing to do a blurred (in this case Offset 100, radius 10) shadow, not hard edged. But I find that if the light direction is from top left as an example, the shadow extends towards the bottom right (expected). This works fine on a straight line mask (say from bottom left to top right), but if the object is a round circle in the middle of the image, the shadow slowly fades as it wraps around the circle back towards the direction of the light, however it continues past the point that the light should prevent a shadow from existing. In fact if the background is white and the object is white, one can see a diminishing shadow all the way along the lit side of the circle (a close look at the circle image I posted), which it shouldn't have. Of course the darker the background, the less this is visible. I only noticed it as I was working white on white, but it is still visible on backgrounds which are less dark than the shadow.
Re: Drop Shadow
I am having trouble deciphering your message. Can you list, one after the other, the steps you are taking that produce an unexpected result?
I believe the drop shadow is being computed correctly -- blurring of the drop shadow is modeling what happens in the real world when the light source is not a point source. This implies that light is coming from more than one direction at a time.
I believe the drop shadow is being computed correctly -- blurring of the drop shadow is modeling what happens in the real world when the light source is not a point source. This implies that light is coming from more than one direction at a time.
Jonathan Sachs
Digital Light & Color
Digital Light & Color
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Marpel
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- Joined: September 13th, 2009, 3:19 pm
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Re: Drop Shadow
No worries.
For the DS, Last Settings:
- open an image and the DS dialogue > identify a mask > enter the parameters (change from default 10 to 50) > OK.
- open the new image and the DS dialogue (Offset is back to 10) > identify (new) mask > Last Settings. The new mask overlay is shown on the image and the Offset is showing in the dialogue as 50 (from last settings) > OK. The resultant image has the correct placement of the DS as it relates to that latest mask, but the shadow is narrower (so Offset 10) than it should be for Offset 50.
For second issue:
Showing steps doesn't have any relevance and after doing the operation again, I think I may see where my confusion partially comes from. I have been assuming the light source is some distance from the "object", where I think the image may suggest the light source is extremely close to the object (So the farther away from the object the light source is the shadow should start farther along the curved surface towards the shadow side).
Having said that, in the image I posted of the "sphere", there is a visible faint line all the way around the sphere to a point closest to the source (unless my eye are playing tricks on me). There should be no shadow on that lit side adjacent (?) to the light source. If one were to take a cylinder (stood up) and shine a flashlight on it from the side, there will be no shadow visible on the side of the cylinder where it receives the direct light. Of course, the farther along the curved edge, away from the light, a shadow starts to appear.
For the DS, Last Settings:
- open an image and the DS dialogue > identify a mask > enter the parameters (change from default 10 to 50) > OK.
- open the new image and the DS dialogue (Offset is back to 10) > identify (new) mask > Last Settings. The new mask overlay is shown on the image and the Offset is showing in the dialogue as 50 (from last settings) > OK. The resultant image has the correct placement of the DS as it relates to that latest mask, but the shadow is narrower (so Offset 10) than it should be for Offset 50.
For second issue:
Showing steps doesn't have any relevance and after doing the operation again, I think I may see where my confusion partially comes from. I have been assuming the light source is some distance from the "object", where I think the image may suggest the light source is extremely close to the object (So the farther away from the object the light source is the shadow should start farther along the curved surface towards the shadow side).
Having said that, in the image I posted of the "sphere", there is a visible faint line all the way around the sphere to a point closest to the source (unless my eye are playing tricks on me). There should be no shadow on that lit side adjacent (?) to the light source. If one were to take a cylinder (stood up) and shine a flashlight on it from the side, there will be no shadow visible on the side of the cylinder where it receives the direct light. Of course, the farther along the curved edge, away from the light, a shadow starts to appear.