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Some Keyshot Tips

Tutorial by FredSWUG
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Keyshot is pretty easy to use, but there are some tips and tricks which can boost the quality of your output.
These are some of the tips I've learned. I pass them on to you and hope they give a boost to your rendering abilities.

  1. Step 1: Introduction

    Recently I posted a paint brush model, and received several comments and messages asking details on how it was done. This tutorial will attempt to demonstrate exactly what was done.

    Disclaimer 1: I consider myself an “average user” with Keyshot. I hope my tips will help you get to where

    I am. Then you can learn some better tips and tricks, and show me what to do!

    Disclaimer 2: I doubt many of these tips and tricks are of my own creation. I watch tutorials, and pick up

    good advice here and there. If you see something here that someone else developed, then that is where

    I may have learned it as well. I’m not trying to take credit for anything I learned from someone else. But I

    also don’t keep records on where I learned some new tip.

    If you’d like to follow along download the file(s) at this link:

    https://grabcad.com/library/paint-brush-2-58mm-1


  2. Step 2: Starting with the CAD model

    1.      Fillet everything. It leads to bigger slower files, but it really improves the appearance of the render.

    2.      Keyshot has a “Rounded Edges” option. I’ve never had much luck with it. It is meant to (obviously) round the sharp edges. If you have a decent CAD model, just add fillets there, you have much more control.

    3.      I split the CAD model up into colors. The color does not matter. Just select all the features, faces, and bodies you want from one material, and apply a color to them.

    a.      If I am working with something like a block of wood where I’ll need directional fibers, and end grain, I’d want to split that simple block into three different colors. Otherwise the mapping will be wrong, and two of the face sets will look terrible.

    b.     If you are working with models that support UV mapping, then that is what you should be using. I deal with SolidWorks models, so no UV mapping.

    4.      I prefer to save a SolidWorks model out as a Parasolid or Step file, and then import it into Keyshot.

    a.      Keyshot will read native SolidWorks files, but eventually SolidWorks will do an update, and Keyshot won’t read the new files until an update. It is easier for me to just use the same method each time.

    b.     Parasolid files work great each time. I’ve discovered that only the newer Step AP214 file option exports model colors. Use an AP2013 version and you don’t get the colors you added above in Step 3.

  3. Step 3: Importing a file into Keyshot

    1.      On the import screen, I import NURBS data. It takes a little longer, but the data is there, and of good quality, so why not use it?

    2.      Before doing anything, check and set the units of the scene (inches). The only time this is really critical is if I plan to add a few different models to a scene. If only using a single model, I have not noticed that the units make a big difference, but it can get confusing when you don’t get the result you expected, and discover that it works only after setting a texture scale to .0001, or .001 instead of the 1 METER it defaulted to.

    3.      Rotate the model so it is in the correct orientation.

    4.      Snap the model to the ground.

    a.      This does not work sometimes. I have no idea why. When that happens, drag the control handle until the model touches the ground. Try to avoid levitating parts, or having your model stuck in the floor!

    b.     Switch the camera to a “side view”. And see how the part looks. The paint brush is a good example. The brush touches the floor, but the handle hovers.



    c.      Rotate and move the part as needed to have the correct ground contact. Sure it is only a third of a degree, but the little things can matter.

  4. Step 4: Setting up the scene in Keyshot

    1.      Rotate the model to the desired view orientation for your render.

    a.      I want to see and focus on the paint brush, so ZOOM in. No sense seeing a paint brush from several feet away! Think about advertising you’ve seen, it features the part, not the back and foreground.



    2.      Now that you like the view, create a new camera, and lock the existing camera so you don’t accidently move anything.

    3.      Apply material(s). I want a wood handle, a shiny nickel metal, and bristles… This is easy; “Light Oak” looks nice. Polished Nickel is an easy choice. Bristles…? We’ll deal with those later.



    4.      Next is lighting. Scene / studio lighting can work sometimes, but since I started using HDRI environments, they really seem the better option. I’m using Dosch-Stairwell_2k.



    a.      Look at the polished nickel; it no longer has that washed out look. The ribbed details stand out much better. The wood even has a nice highlight on the curve. The only problem is the background. Why is a paintbrush laying in a concrete stairwell?

    5.      I’ve seen a few amazing renders where the background matches the model really well. Usually the result ranges from “passable” to “disaster”. I know my limits; I try to stick to solid backgrounds. I avoid “white” and “black”. Few things are pure black, or white. Pick something “close to white” or “close to black”. I used the HSV value of 0°, 0%, 12%.

  5. Step 5: Adjusting materials

    1.      The wood grain is going in the wrong direction. Edit the material and rotate it 90°. Also, the nickel is too perfect. This is a paintbrush, not a precision instrument. Adjust the “roughness” slider to tone it down. I used .03


    2.      Sharp eyed observers may notice that the wood grain in the handle has a problem. The “sides” are now going in the wrong direct. Maybe we can fix this by splitting the geometry into more regions? Keyshot has a utility that allows this type of editing, but I’ve never used it. I’d usually edit it in SolidWorks, export a new model, and then update the Keyshot scene with the new geometry. But, in this case it was getting late, and I wanted to go to bed, so I “cheated”.


    a.      Yup, I rotated the model to try and hide the problem area. Not my finest solution, but I’m showing you how this image came about. The defect(s) can still be seen though. With UV mapping this would not be an issue (from what I hear), but I don’t have access to that kind of magic.


     3.      A while back I watched a Luxion tutorial about Procedural Textures. They will wrap perfectly around complex geometry without the need for UVs. Let’s try one of those!

     Instead of using the “Light_Oak.jpg” as the texture map, set the material texture to use the “Wood (Advanced)” procedural texture.


    a.      Scale, reduce it to .4 or so.

    b.      Rotation, use the Mapping Tool to rotate 90°

    c.      The paintbrush I had in my hand as a reference had some type of yellow, orange/brown varnish on the handle, and it was difficult to see the wood grain.… (You do look at actual objects, or at least photos of objects you are trying to render right? You need to do this). To “fix” this, let’s adjust the colors. The default colors are on the left; my colors are on the right.




    d.     I think the only other settings I changed were: Grain Scale (3.02), Grain Thickness (1.947), and Seed (116). No magic was used to get these values. I just typed in a number, and moved the slider until it “looked better”. I also adjusted the Roughness to better approximate what I had in my hand (.071 became .123)


    e.     Lastly I edited the Material Graph. I just discovered the material graph, so I pretty much have no idea what I am doing. Sometimes I think I figured it out. But that is often my last thought just before something completely unexpected happens to the image.

    f.       The default Material Graph is on the top, modified on the bottom.


  6. Step 6: Final Tweaks

    1.      Here I might rotate the scene to get better lighting.

    2.      The HDRI lighting and entire environment can be adjusted. I try not to mess with it, as I have no idea what I’m doing and the results are usually worse than when I started.

    3.      Sometimes I adjust the Image Brightness and Gamma sliders to make the scene look better. I tend to make it as bright as reasonable in Keyshot, while trying to avoid hot spots of blinding pure white.

    4.      I don’t often use Depth of Field, but now is when I’d apply it.

    5.      Sometimes I use the Vignetting to good effect, but you could do it later in a photo editor for more control.

    6.      I tend to leave the Lighting setting as basic unless I have transparent parts, liquid, or lights. But, I don’t use those materials often.

  7. Step 7: Rendering Images

    1.      My first render is most often a 1024x678 PNG with 96 DPI.

    a.      For output quality, I usually leave it on Maximum Samples, and I typically use a value ranging from 60 – 96.

    b.     I usually turn on the Clown Pass” option for this render as it can be helpful later in a photo editor to generate selections and masks.

    c.      In one tutorial, they showed a great way to get the value to use for Maximum Samples. Press “H” to show the Heads up Display. Now allow the model to “res up” until it “looks good”. Look at the Samples Count in the HUD, and use this, or a close number for your maximum samples setting.

    2.      My next render tends to be a “shadow pass”. This gives some added depth to the image. It is easy to create, just do this:

    a.      Set the background color to pure white, and turn off Ground Shadows.

    b.     Set every part in the scene to use Occlusion as the material.

    c.      Under the Image tab, set the Brightness to 2, and Gamma to 1. Sometimes you’ll need to adjust these numbers. The goal is usually a white part that blends with the background. But, all the spots that light does not reach will have an exaggerated shadow.

    d.     Some people suggest setting the environment to “Shadow Pass”… This makes sense sometimes, but it also causes the shadows to be out of synch with the lighting environment used in the scene. I leave the environment unchanged, unless I have a lot of odd color cast to the scene from colored lights.

    e.      For the shadow pass render I often set the output to include the Alpha (Transparency), but I often forget to do so just as often. Leaving a background will usually have a slight effect on the background color in the final image.

    3.      In a photo editor, put the two images on different layers. You want the shadow pass to be on top of the main image.

    a.      Set the shadow pass layer to “Multiply”, and then adjust its opacity (often 50 – 70%) to taste. Here is a side by side image of without (left), and with (right) the shadow pass layer.




  8. Step 8: What about the bristles?

    1.      I don’t know how to make bristles in Keyshot. I think you can use a program like Zbrush, or Studio Max to define hair and fur, but that is beyond me at this time. I tried a few things with transparent materials, and some textures, but nothing looked good or normal. This was my best try as the clock crept still later in the evening.


    2.      Another issue with the bristles is the same texture mapping problem that came up when using “Light Oak”. The “sides” of the brush simply look terrible, and I did not want to try and recolor them. It was simply easier to not focus on the bristles, and push them off the screen and make sure the model was oriented to not show the sides of the bristle areas.

    3.      Next, I went online and did an image search for a paint brush, and set the search results to show the larger results first. I used the right most image.


    4.      Then it was back to image editing. A new layer was made with a layer mask, and I simply “painted” the bristles from one layer, into a selected area in the other image. The end result was the first image in this document. 




  9. Step 9: Bristles, another option

    1.      I thought of another way to do “bristles” in Keyshot just in case anyone thinks the photo merging method was cheating.

    2.      I set the “brush” material to a generic “Paint” material

    a.      Next I apply a cropped out portion of the bristles from the online image as a bump map. From what I’ve seen, texture images are typically “grayscale images”, so I de-saturated the cropped bristle image in an image editor before I used it as a texture. It looked like this.

    b.     On the model it looked like this.

    c.      Rotate the texture by 90° or 270° depending on what looks best. Change the scale from 1 to .778. An adjustment to Roughness, since I don’t want “glossy paint”, I want it to be some sort of synthetic fiber. Then change the color of the “paint” from “baby blue”, to HSV value 57°, 58%, 51%. These are not magic values. I simply needed a “green/yellow” to look like the brush in my hand. It would have been even easier to photography my existing brush, and use the Keyshot Eyedropper tool to sample the colors I wanted.

     

    d.     The result is “not bad”. I still don’t like the “side bristles” that can be seen, but it might be fixable by setting another color in the CAD model.

    3.      Lastly, I edited the Material Graph a little for the bristles. I added another “plastic material” as a label. Then duplicated the texture to use it as input for the Diffuse and Opacity settings.

    4.      The result gives a greater range of colors in the bristles. There are now more “grays” and “whites” with a hint of a desired green/yellow tint.




  10. Step 10: Conclusion

    I think the difference is noticeable and worth the extra effort. I think the above modifications can be completed quickly once you have the workflow figured out and have done it a few times.

    Why not do your own rendering of the paint brush and post them into the comment section so I can see what you’ve done?



Comments

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    FredSWUG

    Thanks dhananjay. You already make good rendered images, I hope this was still useful for you.

    July 20th, 2017 17:05
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